Fusion, resonances and scattering in 12C+12C reaction
B Sahu; S K Agarwalla; C S Shastry
2003-07-01
The variation of fusion cross-section (fus) with energy in the 12C+12C collision is linked to the underlying resonance phenomenon through the behavior of reaction cross-section (r) of which fus is taken as a part. The calculation of fus is done through an energy-dependent imaginary potential in the optical model potential (OMP). Through dispersion relation, such an imaginary potential gives rise to energy-dependent real potential which is incorporated in the OMP. In our calculation, a form of potential for the nuclear part which has a soft repulsive in-built core is introduced based on similar works done earlier. The calculated results of fus are used to explain the oscillatory structure, astrophysical -factor and the decreasing trend at higher energies of the experimental fus data in the case of 12C+12C system with remarkable success. The potential used for fusion calculation is tested for ﬁtting elastic scattering data at some energies and is found good in forward angles. Further improvement of the ﬁtting of these data is obtained by incorporating a coupling potential in the surface region. About twenty resonances are observed in our calculation in the speciﬁc partial waves and some of them are found close to the experimentally identiﬁed resonances in 12C+12C reaction. Thus, we provide an integrated and comprehensive analysis of fusion, resonance and scattering data in the best studied case of 12C+12C reaction within the framework of optical potential model.
Resonant behavior of the elastic 12C-16O scattering
The angular distributions for 12C-16O elastic scattering at Tandem energies were measured for low energy steps (320keV c.m.) with an excitation function. The shape of the cross section, especially the oscillation phase, presents few changes in the regions where theta 150 deg; on the other hand very fast changes in the form are observed as a function of energy, in the intermediate region. The excitation function shows the existence of three resonances
YANG Yong-Xu; LI Qing-Run; ZHAO Wei-Qin
2002-01-01
Based on the analyses of the elastic angular distributions,an energy-dependent folding potential for the 12C+12C system is established.This potential has a deep real part,and can reasonably well describe the resonant structure in the 12C+12C elastic scattering in the low-energy region of 10 ～ 70 MeV.
$^{-} - {}^{12}C$ elastic scattering above the resonance using diffraction model
M R Arafah
2008-01-01
Phenomenological analysis of the $^{-}- ^{12}C$ elastic scattering differential cross-section at 400, 486, 500, 584, 663, 672 and 766 MeV is presented. The analysis is made in the diffraction model framework using the recently proposed parametrization of the phase-shift function. Good description of the experimental data is achieved at all energies. Microscopic interpretation of the parameters of the phase-shift function is provided in terms of Helm's model density parameters.
Levels in 13N examined by 12C+p elastic resonance scattering with thick target
无
2008-01-01
The elastic resonance scattering of 12C+p has been studied in inverse kinematics via a novel thick target method at GIRAFFE facility of HI-13 tandem accelerator laboratory,Beijing.The recoil protons were measured by a △E-E counter telescope based on a large area double-sided silicon strip detector at laboratory angles around θ0=15°.The excitation function for 12C(p,p)elastic scattering has been obtained over a wide energy range of Ec.m.=0.31-3.45 MeV,which was explained quite well by the R-matrix calculation with known resonance parameters of the first three levels in 13N nucleus.Thus it is demonstrated that the present setup can be directly applied to the study of elastic resonance scattering with secondary radioactive beams.
Spectroscopy of 16O using α + 12C resonant scattering in inverse kinematics
A measurement of α + 12C resonant scattering in inverse kinematics has been performed using resonant scattering with a gas target. The main advantage of this is that unlike previous experiments [1-3] where an excitation function of 16O was scanned using many different beam energies, a He gas target allows a range of resonances in 16O to be traced out as the 12C nuclei loose energy in the target. As such, many resonances can be obtained at single beam energy, without significant loss in the quality of data compared with that of a normal kinematics experiment. Beam energies of 46, 52, 56 and 63 MeV were used to populate resonances in the excitation energy range of 11.6 to 22.9 MeV in 16O. The angular distributions of the elastic scattering were measured at zero degrees, using an array of segmented silicon strip detectors with a minimum range of 0o to 30o in the centre-of-mass. The spins of 8 resonances between 14.01 and 18.47 MeV were obtained, confirming spin assignments made using elastic scattering in normal kinematics. An R-matrix analysis of the data was performed which indicates that the present understanding of 16O, in this region, is good but not complete.(author)
{sup 12}C+p resonant elastic scattering in the Maya active target
Sambi, S.; Raabe, R.; Flavigny, F.; Khodery, M. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Physics Department, Leuven (Belgium); Borge, M.J.G. [CERN, PH Department, Geneva (Switzerland); Caamano, M.; Fernandez-Dominguez, B. [Universidade de Santiago de Compostela, Department of Particle Physics, Santiago de Compostela (Spain); Damoy, S.; Grinyer, G.F.; Pancin, J.; Perez-Loureiro, D.; Roger, T. [CEA/DSM - CNRS/IN2P3, Grand Accelerateur National d' Ion Lourds (GANIL), Caen (France); Fynbo, H. [Aarhus University, Department of Physics and Astronomy, Aarhus (Denmark); Gibelin, J. [Universite de Caen, CNRS/IN2P3, LPC Caen, ENSICAEN, Caen Cedex (France); Heinz, A.; Jonson, B.; Nilsson, T.; Thies, R. [Chalmers University of Technology, Department of Physics, Goteborg (Sweden); Orlandi, R. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Physics Department, Leuven (Belgium); Instituto de Estructura de la Materia CSIC, Madrid (Spain); JAEA, ASRC, Tokai-mura (Japan); Randisi, G. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Physics Department, Leuven (Belgium); CEA/DSM - CNRS/IN2P3, Grand Accelerateur National d' Ion Lourds (GANIL), Caen (France); Ribeiro, G.; Tengblad, O. [Instituto de Estructura de la Materia CSIC, Madrid (Spain); Suzuki, D. [Universite Paris-Sud, Institut de Physique Nucleaire, CNRS/IN2P3, Orsay (France); Datta, U. [Saha Institute of Nuclear Physics, Kolkata (India)
2015-03-01
In a proof-of-principle measurement, the Maya active target detector was employed for a {sup 12}C(p, p) resonant elastic scattering experiment in inverse kinematics. The excitation energy region from 0 to 3MeV above the proton breakup threshold in {sup 13}N was investigated in a single measurement. By using the capability of the detector to localize the reaction vertex and record the tracks of the recoiling protons, data covering a large solid angle could be utilized, at the same time keeping an energy resolution comparable with that of direct-kinematics measurements. The excitation spectrum in {sup 13}N was fitted using the R-matrix formalism. The level parameters extracted are in good agreement with previous studies. The active target proved its potential for the study of resonant elastic scattering in inverse kinematics with radioactive beams, when detection efficiency is of primary importance. (orig.)
Photon scattering from 12C and 4He nuclei near the Δ(1232) resonance
Igarashi, R.; Bergstrom, J. C.; Caplan, H. S.; Doss, K. G. E.; Hallin, E. L.; Skopik, D. M.; Delli Carpini, D.; Booth, E. C.; McIntyre, E. K.; Miller, J. P.; Lucas, M. A.; MacGibbon, B. E.; Nathan, A. M.; Wells, D.
1995-08-01
Angular distributions for photon scattering from 12C and 4He have been measured using continuous wave bremsstrahlung from the Saskatchewan Accelerator Laboratory pulse stretcher ring. Data for carbon were taken at 158.8, 195.2, 197.2, 247.2, and 290.2 MeV end-point energies, and for helium were taken at an end-point energy of 158.8 MeV. A large NaI(Tl) gamma ray spectrometer with 1.7% resolution was used to detect the scattered photons at laboratory scattering angles ranging from 20° to 150°. The excellent energy resolution of the NaI detector allowed a separation of elastic from inelastic photon scattering for the first time at these energies. The angular distributions for elastic scattering are in only fair agreement with delta-hole theory and theory based on the optical theorem at forward angles, and completely disagree with theory at backward angles. Measured cross sections for inelastic scattering leading to the 4.43 MeV state in carbon are small compared to the elastic scattering at forward angles, but are dominant at backward angles. This experiment is the first to separate elastic from inelastic photon scattering at these energies.
Photon scattering from 12C and 4He nuclei near the Δ(1232) resonance
Angular distributions for photon scattering from 12C and 4He have been measured using continuous wave bremsstrahlung from the Saskatchewan Accelerator Laboratory pulse stretcher ring. Data for carbon were taken at 158.8, 195.2, 197.2, 247.2, and 290.2 MeV end-point energies, and for helium were taken at an end-point energy of 158.8 MeV. A large NaI(Tl) gamma ray spectrometer with 1.7% resolution was used to detect the scattered photons at laboratory scattering angles ranging from 20 degree to 150 degree. The excellent energy resolution of the NaI detector allowed a separation of elastic from inelastic photon scattering for the first time at these energies. The angular distributions for elastic scattering are in only fair agreement with delta-hole theory and theory based on the optical theorem at forward angles, and completely disagree with theory at backward angles. Measured cross sections for inelastic scattering leading to the 4.43 MeV state in carbon are small compared to the elastic scattering at forward angles, but are dominant at backward angles. This experiment is the first to separate elastic from inelastic photon scattering at these energies
Microscopic analysis of t+12C scattering
Optical model calculations with double-folded microscopic real central and spin-orbit potentials and an imaginary Woods-Saxon potential have been carried out for previously reported t+12C and 58Ni elastic scattering data. The t+12C calculations are not able to reproduce the changes in the measured analyzing powers as a function of bombarding energy, whereas they do describe the t+58Ni data. This analysis suggests that information about the cluster-core t+12C spin-orbit potential, necessary for cluster structure calculations, cannot be determined without considerably more data. Three-particle-transfer reactions leading to 15N show numerous structures that could appear in the t+12C entrance channel. Excitation functions are needed for both the elastic and 4.43 MeV first excited state in 12C if this scattering is to be understood
12C + 12C resonances by a molecular model
Resonances observed in the 12C + 12C collisions are studied with a molecular model. At high spins J = 12–16, a stable dinuclear configuration is found to be an equator- equator touching one as is obtained in the 28Si + 28Si system. With K-quantum number being specified as rotation-vibration model, normal modes have been solved around the equilibrium, firstly. Furthermore, Coriolis coupling has been investigated by diagonalization among low- lying normal-mode states with K = 0 and K-excitation. It is found that the Coriolis coupling introduces about 30% of K-mixing into the K = 0 molecular ground states of J = 12–16. The analyses of the angular momentum coupling show up a dominance of the lowest L in the inelastic channel of the molecular ground state newly obtained. Thus alignments appear strongly in the inelastic channel, which is in agreement with the explanation by the band crossing model. Discussion is given on ''why disalignments appear in the 28Si + 28Si system, in contrast to the above results''
Angular correlation measurements for {sup 12}C{sup 12}C,{sup 12}C{sup 12}C 3{sup -} scattering
Wuosmaa, A.H.; Betts, R.R.; Freer, M.
1995-08-01
Previous studies of inelastic {sup 12}C + {sup 12}C scattering to a variety of final states identified significant resonance behavior in a number of different reaction channels. These resonances can be interpreted as either potential scattering resonances, or as population of cluster structures in the compound nucleus {sup 24}Mg, or as some interplay between the two mechanisms. Currently, for many of these resonances the situation remains unclear. One example is a large peak observed in the excitation function for the 3{sup -} - g.s. excitation, identified in previous work performed at the Daresbury Laboratory in England. This peak is observed at the same center-of-mass energy as one observed in the O{sub 2}{sup +}-O{sub 2}{sup +} inelastic scattering channel. That structure was suggested to correspond to exotic deformed configurations in the compound nucleus {sup 24}Mg. As the peak in the 3{sup -} + g.s. exit channel occurs at precisely the same energy as the purported resonance, it is tempting to associate the two. Before such an association can be confirmed or ruled out, further information must be obtained about the 3{sup -} + g.s. structure. In particular, it is important to determine the angular momenta that dominate the 3{sup -} + g.s. structure.
Solving the 12C+12C scattering puzzle: is there the '4th elephant'?
Differential cross sections of the 12C+12C and the 13C+12C elastic scattering were measured at the projectile energies 240 MeV (12C) and 250 MeV (13C) up to the largest angles. The positions of the 1st Airy minima known from the former experiments were confirmed.
Spin alignment and resonances in the system 12C+12C - a study with a 4π gamma-spectrometer
In order to characterize the resonance behaviour of 12C+12C in the rotational degrees of freedom in the present thesis the alignment of the intrinsic spin(s) in the reactions 12C12C → 12C+12C* (2+, 4.44 MeV) and 12C+12C → 12C*(2+)+12C*(2+) was studied for nine incident energies in the range 19.29 ≤ Ec.m. ≤ 34.65 MeV in dependence on the scattering angle 400 c.m. ≤ 900. From the position-sensitive detection of the particle-particle coincident 4.44-MeV photons by the Darmstadt-Heidelberg crystal-ball spectrometer the scattering amplitudes characterized by the spin-orientation quantum number m for the single-inelastic scattering could be determined nearly completely. Their angular dependence was subjected to a partial wave analysis as its result the angular-momentum distribution is obtained as function of the incident energy and the m quantum number. For the double-inelastic 12C+12C scattering from the 2-photon intensity distribution the probabilities of the correlated alignment of both fragment spins were derived. (orig./HSI)
/sup 12/C+ /sup 12/C elastic scattering excitation functions and phase shift analysis
Ledoux, R.J.; Bechara, M.J.; Ordonez, C.E.; Al-Juwair, H.A.; Cosman, E.R.
1983-03-01
The /sup 12/C+ /sup 12/C elastic scattering has been measured for E/sub c.m./ = 14.6--31.3 MeV, theta/sub c.m./ = 30/sup 0/--110/sup 0/. The elastic data have been analyzed via a phase shift analysis, enabling the extraction of model independent sets of phase shift parameters. The extracted J/sup ..pi../ values for the intermediate structure resonances at E/sub c.m./ = 18.4, 19.3, and 20.3 MeV are 12/sup +/, 12/sup +/, and 12/sup +/ or 14/sup +/, respectively. The questions of ambiguities in the phase shift analysis and the comparison with J/sup ..pi../ values deduced from other experiments are discussed. Evidence is presented for the existence of gross structure resonances. The elastic scattering has also been analyzed using the sum-of-differences method to directly extract the total reaction cross section. The results of these analyses are compared to existing models of the origin of intermediate structure resonances.
Is there a giant monopole resonance in 12C
Arguments that the 0+ (Esub(x)=20.3 MeV) state recently found in 12C can be interpreted as a giant resonance are given. The calculations of differential cross sections of the 0+ state excitation in elastic and inelastic scattering of 3He, 4He and 6Li on 12C and compared with experimental data. Using transition densities calculated in the hyperspherical function method it is shown that in the framework of the collective model this single state exhausts the monopole energy weighted sum rules
The Ec.m.=32.5 MeV resonance in 12C+12C
It has been suggested that the resonance found at Ec.m. = 32.5 MeV in an inelastic channel of 12C + 12C corresponds to a sic alpha-particle chain state. Re-examining our earlier data on this system a resonance is observed at the same energy in another outgoing channel, 16O + 8Be, which is not expected to resonate for such a configuration. We observe similar angular distributions but an appreciably narrower width than that measured in the inelastic channel. (authors). 11 refs., 2 figs
Bosted, P E; Amarian, M; Anefalos, S; Anghinolfi, M; Asryan, G; Avakian, H; Bagdasaryan, H; Baillie, N; Ball, J P; Baltzell, N A; Barrow, S; Batourine, V; Battaglieri, M; Beard, K; Bedlinskiy, I; Bektasoglu, M; Bellis, M; Benmouna, N; Biselli, A S; Bonner, B E; Bouchigny, S; Boiarinov, S; Bradford, R; Branford, D; Brooks, W K; Bültmann, S; Burkert, V D; Butuceanu, C; Calarco, J R; Careccia, S L; Carman, D S; Carnahan, B; Cazes, A; Chen, S; Cole, P L; Collins, P; Coltharp, P; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Credé, V; Cummings, J P; De Masi, R; De Vita, R; De Sanctis, E; Degtyarenko, P V; Denizli, H; Dennis, L; Deur, A; Djalali, C; Dodge, G E; Donnelly, J; Doughty, D; Dragovitsch, P; Dugger, M; Dharmawardane, K V; Dytman, S; Dzyubak, O P; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Eugenio, P; Fatemi, R; Fedotov, G; Feuerbach, R J; Forest, T A; Fradi, A; Funsten, H; Garçon, M; Gavalian, G; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Golovatch, E; Gothe, R W; Griffioen, K A; Guidal, M; Guillo, M; Guler, N; Guo, L; Gyurjyan, V; Hadjidakis, C; Hafidi, K; Hakobyan, R S; Hardie, J; Heddle, D; Hersman, F W; Hicks, K; Hleiqawi, I; Holtrop, M; Huertas, M; Hyde-Wright, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Ito, M M; Jenkins, D; Jo, H S; Joo, K; Jüngst, H G; Kalantarians, N; Keith, C; Kellie, J D; Khandaker, M; Kim, K Y; Kim, K; Kim, W; Klein, A; Klein, F J; Klusman, M; Kossov, M; Kramer, L H; Kubarovski, V; Kühn, J; Kuhn, S E; Kuleshov, S V; Lachniet, J; Laget, J M; Langheinrich, J; Lawrence, D; Ji Li; Lima, A C S; Livingston, K; Lü, H; Lukashin, K; MacCormick, M; Markov, N; McAleer, S; McKinnon, B; McNabb, J W C; Mecking, B A; Mestayer, M D; Meyer, C A; Mibe, T; Mikhailov, K; Minehart, R; Mirazita, M; Miskimen, R; Mokeev, V; Morand, L; Morrow, S A; Moteabbed, M; Müller, J; Mutchler, G S; Nadel-Turonski, P; Nasseripour, R; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niroula, M R; Niyazov, R A; Nozar, M; O'Rielly, G V; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Paterson, C; Philips, S A; Pierce, J; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Qin, L M; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Rosner, G; Rossi, P; Rowntree, D; Rubin, P D; Sabati, F; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Sharabyan, Yu G; Shaw, J; Shvedunov, N V; Skabelin, A V; Smith, E S; Smith, L C; Sober, D I; Stavinsky, A; Stepanyan, S S; Stepanyan, S; Stokes, B E; Stoler, P; Strauch, S; Suleiman, R; Taiuti, M; Taylor, S; Tedeschi, D J; Thoma, U; Tkabladze, A; Tkachenko, S; Todor, L; Ungaro, M; Vineyard, M F; Vlassov, A V; Weinstein, L B; Weygand, D P; Williams, M; Wolin, E; Wood, M H; Yegneswaran, A; Yun, J; Zana, L; Zhang, J; Zhao, B; Zhao, Z
2007-01-01
The ratio of inclusive electron scattering cross sections for 15N/12C was determined in the kinematic range 0.8
Neutrino neutral-current elastic scattering on 12C
Butkevich, A. V.; Perevalov, D.
2011-01-01
The neutral current elastic scattering of neutrinos on Carbon and $CH_2$ targets is computed using the relativistic distorted-wave impulse approximation with relativistic optical potential. Results for exclusive and inclusive neutrino reactions on ${}^{12}$C target are presented. We show that the nuclear effects on the shape of four-momentum transferred squared distribution $d\\sigma/dQ^2_{QE}$ in neutrino neutral-current and charged-current quasi-elastic scattering are similar. We also calcul...
Scattering of polarized tritons by 9Be and 12C
The differential cross section and the analyzing power A/sub y/ for 9Be(t,t)9Be and 12C(t,t)12C elastic scattering have been measured at 15 and 17 MeV over the angular range theta/sub lab/ = 17.5--165.00. The data in the forward hemisphere have been analyzed with a standard optical model. A large depth and conventional geometry parameters for the spin-orbit potential have been found. The results of the present analysis are in general agreement with previous work involving polarized tritons scattered from heavy target nuclei and show important differences from investigations of the scattering of polarized helions on light nuclei
Alpha-particle momentum distributions from 12C decaying resonances
The computed α particle momentum distributions from the decay of low-lying 12C resonances are shown. The wave function of the decaying fragments is computed by means of the complex scaled hyperspherical adiabatic expansion method. The large-distance part of the wave functions is crucial and has to be accurately calculated. We discuss energy distributions, angular distributions and Dalitz plots for the 4+, 1+ and 4- states of 12C. (author)
Dispersion effects in elastic electron scattering from 12C
The results of an experiment, especially designed to investigate to what extent dispersion effects contribute to the reaction mechanism of elastic electron scattering from 12C, are presented and discussed. Particular attention is given to the discussion of corrections to parameters used in the calculation of the cross section. Tables of the resulting cross sections are given for the ground state and for the 2+ and 0+ states at, respectively, 4.439 and 7.655 MeV. The one-photon exchange approximation for elastic electron scattering from 12C is investigated by testing the energy dependence of the form factor in the region of the first diffraction minimum. The energy dependence observed is interpreted in terms of dispersion effects. 109 refs.; 33 figs.; 14 tabs
Full text: The fulfillment of planned works on measurements of differential cross sections of elastic scattering of protons on nuclear 12C at the energy region of 350†1050 keV suggests the preparation of thin self - supporting carbon target. The self - supporting target is necessary in order to perform investigations in the total angular range. In the future last data will be used in order to determine optical potentials and scattering phases for this nuclear in the energy range of astrophysical interest. There was prepared target layer of the 12C with natural composition of carbon and of thickness of 17.4 μg/cm2. The spraying was conducted in the vacuum evaporation installation (VUP - 4) by an electron bombardment method. Carbon was sprayed on a glass plate with previously deposited of layer salt. After a heating during 12 hours at the temperature of 150 oC the film of carbon was floated from glass plate and self - supporting target has been picked up on the specially prepared target frame. In order to determine thickness of target there was used the resonance chamber, installed in the protons channel of the accelerator RAC - 2 - 1 (INP NNC RK), with the help of which there was measured energy loss of the protons beam during the passage through target, disposed in the central chamber. For this purpose there was used the reaction 27Al(p,γ)28Si with narrow resonance with ER = 992 keV and with detection of gamma-quanta with Eγ = 1779 keV. On shift of the resonance ER=992 keV in the reaction 27Al(p,γ)28Si, which takes place owing to protons energy loss in the thickness of carbon film, and using table values of brake quantities S(Ep)[MeV·cm2/g] [1], there was determined thickness of this fine film. Such the method allows to determine thicknesses of films in the interval of (10 † 100) mcg/cm2 with the accuracy of not worse than 5%. In the present work there were carried out measurements of angular distributions of cross sections of the elastic scattering 12C
An orthogonality condition model treatment of elastic and inelastic (α, 12C) scattering
Elastic and inelastic scattering of α-particles on the deformed nucleus 12C are investigated in the range of incident α-particle energies of 9 to 11 MeV by using the coupled-channel method with orthogonality condition. A doubly folded potential generated by the shell model wave functions of the α-particle and the deformed nucleus 12C is employed for the relative motion between the α-particle and 12C. Good agreement between theory and experiment is obtained for the elastic and inelastic angular distributions and the resonance structures. It is found, from the Born series expansion of the T-matrix, that the orthogonality constraint stresses the effects of the channel-coupling between the elastic and inelastic processes, and it indicates that the DWBA does not work well in this system. (author)
Resonant and nonresonant behavior of the heavy-ion reaction 14C + 12C
The 14C + 12C reaction has been studied by a kinematic coincidence technique at 13 incident energies ranging from Ec.m.=19.35 to 24.9 MeV. The resonances previously reported from γ-ray yield measurements were observed in the equivalent excitation functions, as well as in the large angle elastic scattering data, of the present measurements. Spin assignments were made to the two resonances in this energy range. These resonances are members of a band with angular momenta several units larger than the grazing values corresponding to 14C and 12C orbiting about each other at a distance significantly outside the strong absorption radius. Other structures which were observed were unrelated to the resonant behavior. (author) 22 refs.; 14 figs
The α8Be cluster model for 02+ resonance of 12C
The two-cluster α + 8Be is used for description of 02+ resonance of 12C nucleus. The equation for relative motion of clusters is derived from the s-wave differential Faddeev equations of the three-α-cluster system. For these aim a simple version of the resonating-group method is applied. A phenomenological potential is employed for description of αα interaction. The three-body potential which binds 3α system ensures the existence of a resonance state in the α + 9Be scattering. The results of our calculations are compared with the results of other authors
Probing the isoscalar excitations of 12C with inelastic alpha scattering
The robust (spin and isospin zero) α-particle remains one of the best projectiles to probe the nuclear isoscalar excitations. In the present work, a microscopic folding model analysis of the α+12C inelastic scattering to the 2+ (4.44 MeV), 0+ (7.65 MeV), 3- (9.64 MeV), 0+ (10.3 MeV) and 1- (10.84 MeV) states in 12C has been performed using the 3-α resonating group method wave functions. The isoscalar transition strengths of these states were carefully studied based on the coupled-channel analysis using the microscopic folded form factors. A correlation between the weak binding and/or short lifetime of the excited state and absorption in the exit channel of inelastic scattering has been established. (author)
Quantum partner-dance in the 12C + 12C system yields sub-Coulomb fusion resonances
A preliminary study of the 12C + 12C sub-Coulomb fusion reaction using the time-dependent wave-packet method is presented. The theoretical sub-Coulomb fusion resonances seem to correspond well with observations. The present method might be a more suitable tool for expanding the cross-section predictions towards lower energies than the commonly used potential-model approximation.
Resonance states in 16O + 16O, 12C + 16O, + 16O and + 12C with modified Morse potentials
B Sahu; L Satpathy
2008-05-01
The resonance states in 16O + 16O, 12C + 16O, + 16O and + 12C are described using modified Morse potential proposed earlier whose success has already been demon-strated in the case of 12C + 12C system. The general validity of such a potential with long range, shallow depth and repulsive soft core determined from the resonance data itself is being examined through the present study of the resonances in the above four systems. In each system, the experimental data of a large number of states have been successfully described with a modified Morse potential. The success points out a common mechanism of the origin of these states, and reaffirms authentically the diatomic-like rotational and vibrational picture of the nuclear molecular resonances proposed previously. The close resemblance between the physics of diatomic molecules and nuclear molecular resonances extending to the level of potential which is Morse type in both the cases - although belong to two different areas of physics - is further strengthened through the present study.
The 90deg excitation function for elastic 12C+12C scattering. The importance of Airy elephants
The 90deg excitation function for elastic 12C+12C scattering, at laboratory energies between the Coulomb barrier and 130 MeV, exhibits a complex structure of peaks and valleys whose nature has remained an unsolved mystery for more than 20 years. The problem has primarily been caused by the difficulty of choosing from a plethora of discretely ambiguous optical potentials. However, data accumulated above 150 MeV over the last decade have determined unique potentials at these higher energies, and the requirement of continuity downward in energy has recently permitted the determination of a unique set of potentials for angular distributions at energies below 130 MeV, where the excitation-function data exist. These new potentials are used to provide a mean-field (i.e., nonresonant) interpretation of the structure in the 12C+12C 90deg excitation function between 70 and 130 MeV. Its most prominent minima are found to be Airy minima from nuclear rainbows, with the remaining structure arising primarily from more elementary optical phenomena related to Fraunhofer diffraction. These same potentials are also successful in explaining the details of excitation functions measured very recently at other angles by Morsad. (orig.)
Measurement of resonances in 12 C + 4 He through inverse kinematics with thick targets
The excitation function of elastic scattering for the system 12 C + 4 He to energy from 0.5 to 3.5 MeV in the center of mass system (c.m.) was measured. We use a gassy thick target and the technique of inverse kinematics which allows to make measurements at 180 degrees in c.m. Using the R matrix theory those was deduced parameters of the resonances and the results were compared with measurements reported in the literature made with other techniques. (Author)
The 12C + 12C reaction is important to understand the nuclear burning in stellar evolution. In this work, we calculate the 12C + 12C microscopic potential based on the effective nucleon-nucleon (NN) interaction and the wave functions of interaction nuclei. The Optical Model analysis for elastic scattering angular distributions of 12C + 12C system at energies near to the Coulomb barrier agrees well with the experimental data, which makes sure the applicability of our obtained potential. The Barrier Penetration Model (BPM) and WKB approximation are applied to estimate the astrophysical S factor, which is reasonable to measurement results. (author)
Microscopic description of the elastic and inelastic 16O+12C scattering
The elastic and inelastic 16O+12C scattering data were described the optical model and DWBA calculations using the folded potential based on the CDM3Y6 interaction and the collective transition densities. The strong nuclear rainbow patterns were expressed in the refractive elastic 16O+12C scattering data at Elab=200, 230 and 260 MeV. The nuclear rainbow patterns in the inelastic 16O+12C scattering was expressed very weakly because of suppression of the strong absorption of optical potential in the exit channel. (author)
Phenomenological local potentials for π-+12C scattering from 120 to 766 MeV
Pion-nucleus scattering cross sections are calculated by solving a Schroedinger equation reduced from the Klein-Gordon equation. Local potentials are assumed, and phenomenological potential parameters are searched energy-dependently for a π-+12C system so as to reproduce not only elastic differential cross sections but also total elastic, reaction and total cross sections at 13 pion incident energies from 120 to 766 MeV. The real and imaginary parts of the local potentials thus obtained are shown to satisfy the dispersion relation. The imaginary part of the potentials as a function of the pion energy is found to peak near the Δ(1232)-resonance energy. The strong absorption radius of the pion projectile with incident energies near the Δ-resonance region is found to be about 1.6A1/3 fm, which is consistent with previous studies of the region where the decay of the Δ takes place in nuclei. The phenomenological local potentials are then compared with the local potentials exactly phase-shift equivalent to Kisslinger potentials for pion energies near the Δ-resonance. (author)
Isoscalar monopole and dipole excitations of cluster states and giant resonances in 12C
Kanada-En'yo, Yoshiko
2016-05-01
The isoscalar monopole (ISM) and dipole (ISD) excitations in 12C are investigated theoretically with the shifted antisymmetrized molecular dynamics (AMD) plus 3 α -cluster generator coordinate method (GCM). The small-amplitude vibration modes are described by coherent one-particle one-hole excitations expressed by a small shift of single-nucleon Gaussian wave functions within the AMD framework, whereas the large-amplitude cluster modes are incorporated by superposing 3 α -cluster wave functions in the GCM. The coupling of the excitations in the intrinsic frame with the rotation and parity transformation is taken into account microscopically by the angular-momentum and parity projections. The present a calculation that describes the ISM and ISD excitations over a wide energy region covering cluster modes in the low-energy region and the giant resonances in the high-energy region, although the quantitative description of the high-energy part is not satisfactory. The low-energy ISM and ISD strengths of the cluster modes are enhanced by the distance motion between α clusters, and they split into a couple of states because of the angular motion of α clusters. The low-energy ISM strengths exhaust 26% of the energy-weighted sum rule, which is consistent with the experimental data for the 12C(02+; 7.65 MeV) and 12C(03+; 10.3 MeV) measured by (e ,e') ,(α ,α') , and (6Li,6Li' ) scatterings. In the calculated low-energy ISD strengths, two 1- states (the 11- and 12- states) with the significant strengths are obtained over E =10 -15 MeV. The results indicate that the ISD excitations can be a good probe to experimentally search for new cluster states such as the 12C(12-) obtained in the present calculation.
Ledoux, R.J.; Ordonez, C.E.; Bechara, M.J.; Al-Juwair, H.A.; Lavelle, G.; Cosman, E.R.
1984-09-01
Excitation functions of the /sup 12/C(/sup 12/C, ..cap alpha..)/sup 20/Ne reaction were measured at Theta/sub lab/ = 7.5/sup 0/ between E/sub c.m./ = 14-40 MeV and angular distributions were measured from E/sub c.m./ = 17.8 to 20.6 MeV. Summed yields reveal prominent intermediate structure resonances over the entire range which correlate well to resonances previously observed in elastic data. The resonances show enhanced decays to excited rotational bands in /sup 20/Ne with reduced widths comparable to those for the elastic channel and an order of magnitude greater than those for the /sup 20/Ne ground state band. A discussion is given of the resonances as shape-isomeric states in a shell model secondary minimum in /sup 24/Mg, and of the selective alpha decay as being transitions to states of related configuration in /sup 20/Ne.
Ledoux, R.J.; Ordoez, C.E.; Bechara, M.J.; Al-Juwair, H.A.; Lavelle, G.; Cosman, E.R.
1984-09-01
Excitation functions of the /sup 12/C(/sup 12/C,..cap alpha..) /sup 20/Ne reaction were measured at theta/sub lab/ = 7.5/sup 0/ between E/sub c.m./ = 14--40 MeV and angular distributions were measured from E/sub c.m./ = 17.8 to 20.6 MeV. Summed yields reveal prominent intermediate structure resonances over the entire range which correlate well to resonances previously observed in elastic data. The resonances show enhanced decays to excited rotational bands in /sup 20/Ne with reduced widths comparable to those for the elastic channel and an order of magnitude greater than those for the /sup 20/Ne ground state band. A discussion is given of the resonances as shape-isomeric states in a shell model secondary minimum in /sup 24/Mg, and of the selective alpha decay as being transitions to states of related configuration in /sup 20/Ne.
A procedure to connect a model-independent phase-shift analysis with the solution of the inverse quantum scattering problem has been developed and applied to experimental differential cross sections of 12C+12C elastic scattering in the energy range Ec.m.=8--12 MeV. The minimization of the error square function χ2 is performed with respect to the spectral coefficients involved in the inverse procedure. Input quantities are measured differential cross sections; output results are complex potentials. The real part of the potentials, so obtained, is characterized by a pronounced minimum value of -(7--14) MeV at relative distances in the range 2.4--3 fm and by a Coulomb barrier of height 6--7 MeV in the outer region around r∼8--9 fm. In addition a second minimum, very shallow or vanishing at some incident energies, is found to exist in the region 5--6 fm. The imaginary part of the potential exhibits positive maxima in those regions of radial distances where the real part has minimum values indicating a possible feedback effect of flux to the elastic channel. The overall energy dependence of the potentials shows a shape transition resulting in diminishing the outer potential minimum between Ec.m. of 9 and 12 MeV. The inverted (real) potentials yield phase shifts of π/2 in those partial waves where resonances are known to exist. The procedure is tested by recalculating differential cross sections from the inverted energy-dependent potentials with the result that consistent agreement with the experimental input data is found
Refractive effects and Airy structure in inelastic $^{16}$O+$^{12}$C rainbow scattering
Ohkubo, S; Ogloblin, A A; Gloukhov, Yu A; Dem'yanova, A S; Trzaska, W H
2014-01-01
Inelastic $^{16}$O +$^{12}$C rainbow scattering to the $2^+$ (4.44 MeV) state of $^{12}$C was measured at the incident energies, $E_L$ = 170, 181, 200, 260 and 281 MeV. A systematic analysis of the experimental angular distributions was performed using the coupled channels method with an extended double folding potential derived from realistic wave functions for $^{12}$C and $^{16}$O calculated with a microscopic $\\alpha$ cluster model and a finite-range density-dependent nucleon-nucleon force.The coupled channels analysis of the measured inelastic scattering data shows consistently some Airy-like structure in the inelastic scattering cross sections for the first $2^+$ state of $^{12}$C, which is somewhat obscured and still not clearly visible in the measured data. The Airy minimum was identified from the analysis and the systematic energy evolution of the Airy structure was studied. The Airy minimum in inelastic scattering is found to be shifted backward compared with that in elastic scattering.
Further evidence for a dynamically generated secondary bow in $^{13}$C+$^{12}$C rainbow scattering
Ohkubo, S; Ogloblin, A A
2015-01-01
The existence of a secondary bow is confirmed for 13C+12C nuclear rainbow scattering in addition to the 16O+12C system. This is found by studying the experimental angular distribution of 13C+12C scattering at the incident 13C energy $E_L$=250 MeV with an extended double folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic wave functions for 12C using a density-dependent nucleon-nucleon force. The Airy minimum at \\theta$ $\\approx$70$^\\circ$, which is not reproduced by a conventional folding potential, is revealed to be a secondary bow generated dynamically by a coupling to the excited state 2+ (4.44 MeV) of 12C. The essential importance of the quadruple {\\it Y2} term (reorientation term) of potential of the excited state 2+ of 12C for the emergence of a secondary bow is found. The mechanism of the secondary bow is intuitively explained by showing how the trajectories are refracted dynamically into the classically forbidden angular region beyond t...
Quasi-bound alpha resonant states populated by the 12C(6Li, d) reaction
Full text: The alpha cluster phenomenon in the light nuclei structure has been the subject of a long time investigation since the proposal of the Ikeda diagrams [1]. The main purpose of the research program in progress is the investigation of this phenomenon in (xα) and (xα+n) nuclei through the (6Li, d) alpha transfer reaction [2-4]. Alpha resonant states around the (4α) threshold in the nucleus 16O are the focus of the present contribution. In fact, the importance of these resonances at the elements production in stars is recognized, as primarily pointed out by Hoyle in 12C [6]. The existence of a rotational band with the α +12 C (Hoyle) cluster state structure was recently demonstrated by Ohkubo and Hirabayashi [6]. In order to explore this region of interest, measurements of the 12C(6Li, d)16O reaction up to 17 MeV of excitation at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique (plates Fuji G6B, 50 μm thick). Spectra associated with six scattering angles, from 5 deg to 29 deg in the laboratory frame, each one 50 cm along the focal surface, were measured. Several narrow resonances with a quasi-bound behavior embedded in the continuum were detected and the resolution of 25 keV allowed for the separation of doublets not resolved before [7,8]. The absolute cross sections and the respective deuteron angular distributions were determined and the analysis is in progress. [1] K. Ikeda et al., Prog. Theor. Phys. Suppl. E 68, 464 (1968); H. Horiuchi, K. Ikeda, and Y. Suzuki, ibid. 44, 225 (1978). [2] M.R.D.Rodrigues et al., in12th International Conference on Nuclear Reaction Mechanism, Varenna, Italy, edited by F. Cerutti and A. Ferrari , CERN Proceedings, 2010-2, pp. 331- 335. [3] T. Borello-Lewin et al., Proceedings of SOTANCP2, Brussels, Belgium 2010, edited by P. Descouvemount et al., Int. J. Mod. Mod. Phys E 20, 1018-1021 (2011). [4] T. Borello-Lewin et
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...
Elastic scattering of 3He by 12C at 40.9 MeV energy
The elastic scattering of 40.9 MeV 3He-particles from 12C was investigated in the framework of the simple one-channel optical model. An overall good fit could be obtained. The ambiguities of the real central potential are discussed. (author)
Study of elastic and inelastic scattering of 12C on 40Ca and 48Ca
Angular distributions in elastic and inelastic scattering of 12C on 40Ca and 48Ca at 34.6 MeV (c.m.) were measured. The experimental results are presented and discussed using the optical model and the semi-classical analysis
Elastic scattering of 6He from 12C at 38.3 MeV/nucleon
DONG Hong-Fei; MA Yin-Qun; MA Zhong-Yu
2009-01-01
The microscopic optical potential of nucleus-nucleus interaction is presented via a folding method with the isospin dependent complex nucleon-nuclear potential, which is first calculated in the framework of the Dirac-Bruecker-Hartree-Fock approach. The elastic scattering data of 6He at 229.8 MeV on 12C target are analyzed within the standard optical model. To take account of the breakup effect of 6He in the reaction an enhancing factor 3 on the imaginary potential is introduced. The calculated 6He+12C elastic scattering differential cross section is in good agreement with the experimental data. Comparisons with results in the double-folded model based on the M3Y nucleon-nucleon effective interaction and the few the body Glauber-model calculations are discussed. Our parameter free model should be of value in the description of nucleus-nucleus scattering, especially unstable nucleus-nucleus systems.
Excitation function of elastic scattering on 12C + 4He system, at low energies
Interactions in the 12C + 4He system are of great interest in astrophysics and to help determine the relative abundances of elements in stars, at the end of helium burning [1, 2]. The Instituto Nacional de Investigaciones Nucleares (ININ) in Mexico, have made measurements of elastic scattering for this system, using the inverse kinematics method with thick white gas [3, 4], for E CM (0.5 - 4 MeV) θ CM = 180o. In this work we obtain excitation functions of elastic scattering of 12C + 4He system with angular and energy dependence; ECM = 0.5 - 4 MeV and θCM 100o -170o.Using inverse kinematics method with thick white gas and energy loss tables. (Author)
4.2 GeV α-12C Elastic Scattering Based on α-Particle Model
YANG Yong-Xu; LU Xiao; LI Qing-Run
2008-01-01
Based on the a-particle model of 12C nucleus, the differential cross sections for α-12 C elastic scattering at incident energy of 4.2 GeV have been calculated within the framework of Glauber multiple scattering theory. The results show that the main features of the measured angular distribution of the cross sections can be reasonably described. The parameterizedα-α scattering amplitude, which is the basic input to construct the α-12C scattering Glauber amplitude in the a-particle model, is obtained by fitting the α-α scattering data.
Elastic scattering and total reaction cross sections for 8Li+12C
Full text: The elastic scattering angular distribution for 8Li on 12C has been measured at ELAB= 23.9 MeV with 8Li radioactive nuclear beam produced by the Radioactive Ion Beams in Brazil facility (RIBRAS). This angular distribution was analysed in terms of optical model with Woods-Saxon and double-folding Sao Paulo potentials. The roles of the breakup and inelastic channels were also investigated with cluster folding and deformed potentials, respectively, through coupled channels calculations. The angular distributions for the proton-transfer 12C(8Li,9Be)11B reaction was also measured at the same energy, simultaneously with the elastic scattering. The spectroscopic factor for the 9Be I 8Li+p> bound system was obtained through DWBA (Distorted-Wave Born Approximation) calculations with the code Fresco, and compared with shell model calculations and other experimental values. The spectroscopic factor obtained was used for normalization of the capture reaction cross section 8Li(p, gamma)9Begs. The depth of the scattered potential obtained was 40,1 +- 1,6 MeV. The astrophysical S-factor curves and the reaction rate for the capture reaction 8Li(p,gamma)9Begs were calculated. Total reaction cross sections for the present system were also extracted from the elastic scattering analysis. A systematic of the reduced reaction cross section obtained from the present and published data on 6;7;8Li isotopes on 12C was performed as a function of energy. (author)
A fully microscopic model of 200 MeV proton-12C elastic and inelastic scattering
An effective two nucleon (NN) interaction in the nuclear medium is defined from an accurate mapping of the NN g matrices obtained by solving the Brueckner-Bethe-Goldstone equations for infinite nuclear matter. That effective interaction is used in a fully microscopic calculation of the nonlocal effective proton-12C interaction from which are obtained predictions of the differential cross section and analysing power for 200 MeV elastic scattering. The relative motion wave functions so found are used as the distorted waves in a distorted wave approximation (DWA) study of select inelastic scattering events. The effective NN interaction is used as the transition operator in those calculations. The relevant nuclear spectroscopy for the elastic and DWA (p, p') calculations is found from a full (0 + 2) ℎω shell model evaluation of the positive parity states while a restricted (1 + 3)ℎω has been used to give the negative parity states. Results are compared with those of the 0p-shell model of Cohen and Kurath or with those based upon axially symmetric, projected Hartree-Fock calculations. The diverse structure model wave functions are assessed by using them in calculations to compare with measured longitudinal, transverse electric and transverse magnetic form factors from electron scattering to many of the excited states of 12C. Using those models of the structure of 12C in the completely microscopic model of the elastic and inelastic scattering of 200 MeV protons, good fits have been found to the cross section and analysing power data. 50 refs., 3 tabs., 20 figs
Studies of elastic scattering and cross sections of the 12C + 28Si system
Angular distributions of the elastic scattering of the system 12C+28Si were measured at the energies ECM = 14.70; 16.08; 18.90; 20,97; 21.87 MeV, in the angular range 150 ≤ θCM ≤ 1700, with angular steps of 10. Other seven angular distributions measured by Villari, Ost and Cheng at energies ECM = 17.50; 19.60; 20.30; 22.40; 23.80; 24.50 and 25.20 MeV, have also been used in our analysis. The angular distributions have been reproduced by optical model calculations and new optical potentials for the system 12C+28Si were obtained. Calculations of the total reaction cross section from the elastic scattering data using a model independent method were done. The results were compared with fusion cross section data and with total reaction cross sections obtained via optical model calculations. Finally experimental angular distributions were analysed by phase shift analysis and the problem of unicity and ambiguities of the scattering matrix S(l) was discussed. (author)
Neutral weak-current two-body contributions in inclusive scattering from {sup 12}C
Lovato, Alessandro [ANL; Gandolfi, Stefano [LANL; Carlson, Joseph [LANL; Pieper, S. C. [ANL; Schiavilla, Rocco [JLAB, ODU
2014-05-01
An {\\it ab initio} calculation of the sum rules of the neutral weak response functions in $^{12}$C is reported, based on a realistic Hamiltonian, including two- and three-nucleon potentials, and on realistic currents, consisting of one- and two-body terms. We find that the sum rules of the response functions associated with the longitudinal and transverse components of the (space-like) neutral current are largest and that a significant portion ($\\simeq 30$\\%) of the calculated strength is due to two-body terms. This fact may have implications for the MiniBooNE and other neutrino quasi-elastic scattering data on nuclei.
Compton scattering from 12C using tagged photons in the energy range 65 - 115 MeV
Myers, L S; Preston, M F; Anderson, M D; Annand, J R M; Boselli, M; Briscoe, W J; Brudvik, J; Capone, J I; Feldman, G; Fissum, K G; Hansen, K; Henshaw, S S; Isaksson, L; Jebali, R; Kovash, M A; Lewis, K; Lundin, M; MacGregor, I J D; Middleton, D G; Mittelberger, D E; Murray, M; Nathan, A M; Nutbeam, S; O'Rielly, G V; Schröder, B; Seitz, B; Stave, S C; Weller, H R
2014-01-01
Elastic scattering of photons from 12C has been investigated using quasi-monoenergetic tagged photons with energies in the range 65 - 115 MeV at laboratory angles of 60 deg, 120 deg, and 150 deg at the Tagged-Photon Facility at the MAX IV Laboratory in Lund, Sweden. A phenomenological model was employed to provide an estimate of the sensitivity of the 12C(g,g)12C cross section to the bound-nucleon polarizabilities.
16O resonances near 4α threshold through 12C(6Li,d) reaction
Several narrow alpha resonant 16O states were detected through the 12C(6Li,d) reaction, in the range of 13.5 to 17.5 MeV of excitation energy. The reaction was measured at a bombarding energy of 25.5 MeV employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion technique. Experimental angular distributions associated with natural parity quasi-bound states around the 4α threshold are presented and compared to DWBA predictions. The upper limit for the resonance widths obtained is near the energy resolution (15 keV)
Elastic Neutron Scattering at 96 MeV from {sup 12}C and {sup 208}Pb
Klug, J.; Blomgren, J.; Atac, A. [and others
2003-04-01
A facility for detection of scattered neutrons in the energy interval 50-130 MeV, SCANDAL (SCAttered Nucleon Detection AssembLy), has recently been installed at the 20-180 MeV neutron beam line of the The Svedberg Laboratory, Uppsala. Elastic neutron scattering from {sup 12}C and {sup 208}Pb has been studied at 96 MeV in the 10-70 deg interval. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated uncertainty, 3 %, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. The results are compared with modern optical model predictions, based on phenomenology or microscopic nuclear theory.
Elastic Neutron Scattering at 96 MeV from 12C and 208Pb
A facility for detection of scattered neutrons in the energy interval 50-130 MeV, SCANDAL (SCAttered Nucleon Detection AssembLy), has recently been installed at the 20-180 MeV neutron beam line of the The Svedberg Laboratory, Uppsala. Elastic neutron scattering from 12C and 208Pb has been studied at 96 MeV in the 10-70 deg interval. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated uncertainty, 3 %, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. The results are compared with modern optical model predictions, based on phenomenology or microscopic nuclear theory
Using a partial wave analysis the angular distributions measured for the reactions 11B (p,p') 11B* and 11B (p,a) 8Be in the energy range from 4.5 to 7.5 MeV the resonance states of 12C were determined including level widths, spin, parity, and isopin. (HSI)
He, W B; Cao, X G; Cai, X Z; Zhang, G Q
2014-01-01
It is studied how the $\\alpha$ cluster degrees of freedom, such as $\\alpha$ clustering configurations close to the $\\alpha$ decay threshold in $^{12}$C and $^{16}$O, including the linear chain, triangle, square, kite, and tetrahedron, affect nuclear collective vibrations with a microscopic dynamical approach, which can describe properties of nuclear ground states well across the nuclide chart and reproduce the standard giant dipole resonance (GDR) of $^{16}$O quite nicely. It is found that the GDR spectrum is highly fragmented into several apparent peaks due to the $\\alpha$ structure. The different $\\alpha$ cluster configurations in $^{12}$C and $^{16}$O have corresponding characteristic spectra of GDR. The number and centroid energies of peaks in the GDR spectra can be reasonably explained by the geometrical and dynamical symmetries of $\\alpha$ clustering configurations. Therefore, the GDR can be regarded as a very effective probe to diagnose the different $\\alpha$ cluster configurations in light nuclei.
Investigation of 16O+12C refractive elastic scattering using the α-cluster model potential
Differential cross-section of the 16O+12C elastic scattering at Elab = 132, 181, 200, 260, 300, 608 and 1503MeV has been reanalyzed in the framework of double-folding cluster (DFC1) potential over a wide angular range which cover both diffractive and refractive regions. Based upon the α-cluster structure of both colliding nuclei, the real DFC1 optical potential has been generated by using α-α effective interaction and new cluster modified Gaussian (CMGD) of target and projectile has also been extracted. Successful descriptions of the data were obtained over the full measured angular range at all considered energies. The results have been compared with the findings obtained by using the phenomenological approach as well as experimental data. Furthermore, the consistency between the real and imaginary volume integrals is checked by the dispersion relation and the total reaction cross-section has also been investigated. (orig.)
We propose to measure the γ-ray emission probability from excited states above 5 MeV including giant resonance of 16O and 12C as a function of excitation energy in 1-MeV step. Here, we measure both the excitation energy (Ex=5-30MeV) at the forward scattering angles (0°-3°) of the 16O, 12C (p, p’) reaction using Grand-Raiden Spectrometer and the energy of γ-rays (Eγ) using an array of NaI(Tl) counters. The purpose of the experiment is to provide the basic and important information not only for the γ-ray production from primary neutral-current neutrino-oxygen (-carbon) interactions but also for that from the secondary hadronic (neutron-oxygen and -carbon) interactions
Ou, I.; Yamada, Y.; Mori, T.; Yano, T.; Sakuda, M. [Department of Physics, Okayama University, Okayama 700-8530 (Japan); Tamii, A.; Suzuki, T.; Yosoi, M.; Aoi, N.; Ideguchi, E.; Hashimoto, T.; Miki, K.; Ito, T.; Iwamoto, C.; Yamamoto, T. [Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); Akimune, H. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan)
2015-05-15
We propose to measure the γ-ray emission probability from excited states above 5 MeV including giant resonance of {sup 16}O and {sup 12}C as a function of excitation energy in 1-MeV step. Here, we measure both the excitation energy (E{sub x}=5-30MeV) at the forward scattering angles (0°-3°) of the {sup 16}O, {sup 12}C (p, p’) reaction using Grand-Raiden Spectrometer and the energy of γ-rays (E{sub γ}) using an array of NaI(Tl) counters. The purpose of the experiment is to provide the basic and important information not only for the γ-ray production from primary neutral-current neutrino-oxygen (-carbon) interactions but also for that from the secondary hadronic (neutron-oxygen and -carbon) interactions.
Inelastic proton scattering at 30--40 MeV from 12C
Elastic and inelastic proton differential cross sections for excitation of the following levels of 12C: 21+(4.43 MeV), 41+(14.08 MeV), 02+(7.65 MeV), and 31-(9.64 MeV) have been measured at three incident energies between 30 and 40 MeV. The data have been described by coupled channel calculations and form factors obtained by coupling surface vibrations to static deformations. The reproduction of the 02+ state data, if this state is assumed to be a β-vibrational state, requires a quadrupole β-vibrational amplitude which is 57% of the static quadrupole deformation and a mixing of the breathing mode of the nucleus with an amplitude that would correspond to about 1% of the E0 energy weighted sum rule. For the 31- state it is found that the performed calculations are sensitive to the K projection, with the angular distribution of the 31- state being better fitted assuming K/sup π/ = 3- band. Coupled channel calculations using microscopic form factors obtained from wave functions generated using the resonating group method have also been performed and are compared to the experimental data
Quasi-bound alpha resonant states populated by the {sup 12}C({sup 6}Li, d) reaction
Rodrigues, M.R.D.; Borello-Lewin, T.; Miyake, H.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F.; Foti, A.; Agodi, C.; Cavallaro, M. [Istituto Nazionale di Fisica Nucleare (LNS/INFN), Catania (Italy). Lab. Nazionali del Sud; Ukita, G.M. [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Faculdade de Psicologia
2012-07-01
Full text: The alpha cluster phenomenon in the light nuclei structure has been the subject of a long time investigation since the proposal of the Ikeda diagrams [1]. The main purpose of the research program in progress is the investigation of this phenomenon in (x{alpha}) and (x{alpha}+n) nuclei through the ({sup 6}Li, d) alpha transfer reaction [2-4]. Alpha resonant states around the (4{alpha}) threshold in the nucleus {sup 16}O are the focus of the present contribution. In fact, the importance of these resonances at the elements production in stars is recognized, as primarily pointed out by Hoyle in {sup 12}C [6]. The existence of a rotational band with the {alpha} +{sup 12} C (Hoyle) cluster state structure was recently demonstrated by Ohkubo and Hirabayashi [6]. In order to explore this region of interest, measurements of the {sup 12}C({sup 6}Li, d){sup 16}O reaction up to 17 MeV of excitation at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique (plates Fuji G6B, 50 {mu}m thick). Spectra associated with six scattering angles, from 5 deg to 29 deg in the laboratory frame, each one 50 cm along the focal surface, were measured. Several narrow resonances with a quasi-bound behavior embedded in the continuum were detected and the resolution of 25 keV allowed for the separation of doublets not resolved before [7,8]. The absolute cross sections and the respective deuteron angular distributions were determined and the analysis is in progress. [1] K. Ikeda et al., Prog. Theor. Phys. Suppl. E 68, 464 (1968); H. Horiuchi, K. Ikeda, and Y. Suzuki, ibid. 44, 225 (1978). [2] M.R.D.Rodrigues et al., in12th International Conference on Nuclear Reaction Mechanism, Varenna, Italy, edited by F. Cerutti and A. Ferrari , CERN Proceedings, 2010-2, pp. 331- 335. [3] T. Borello-Lewin et al., Proceedings of SOTANCP2, Brussels, Belgium 2010, edited by P. Descouvemount et al., Int. J
Resonantly scattering crystals and surfaces
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)
Diffraction scattering of 7Be and 8B on 12C taking into account the coulomb interaction
The differential cross sections for scattering of 7Be and 8B nuclei on 12C nuclei are calculated in the framework of general theory of diffraction interactions of nuclei consisting of two charged weakly-bound clusters. Available experimental data are analyzed. (author)
Quasi-Elastic Scattering of 16C from 12C at 47.5 MeV/Nucleon
FAN Feng-Ying; ZHENG Tao; YE Yan-Lin; JIANG Dong-Xing; HUA Hui; LI Zhi-Huan; GE Yu-Cheng; LI Xiang-Qing; LOU Jian-Ling; SHI Fan; LV Lin-Hui; CAO Zhong-Xin; NIE Peng-Xuan; LI Qi-Te; SONG Yu-Shou; LU Fei; XU Hu-Shan; HU Zheng-Guo; WANG Meng; ZHANG Xue-Ying; LI Chen; CHEN Ruo-Fu; TANG Bin; XU Zhi-Guo; YUE Ke; ZHANG Ya-Peng; ZANG Yong-Dong; ZHANG Xue-Heng; YAO Xiang-Wu; CHEN Jin-Da; TU Xiao-Lin; ZHANG Jie; WU Da-Peng; BAI Zhen
2009-01-01
Differential cross sections for the quasi-elastic scattering of 16C at 47.5 MeV/nucleon from 12C target are measured.Coupled-channels calculations are carried out and the optical potential parameters are obtained by fitting the experimental angular distribution.
Elastic and inelastic scattering of 800 MeV/c K+- mesons from 12C and 40Ca
Methods and results of an experiment to study the scattering of 800 MeV/c K+- mesons from 12C and 40Ca are presented. The reactions under study include: the four elastic scattering reactions 12C(K+-,K+-) and 40Ca(K+-,K+-), and the four inelastic scattering reactions, 12C(K+-.K+-') to the J/sup P/ = 2+ 4.43 MeV and J/sup P/ = 3- states. The experimental data were obtained using the Hyper-Nuclear Spectrometer and the Low Energy Separated Beam (LESB I) at the Alternating Gradient Synchrotron (AGS) of Brookhaven Laboratory (BNL). Calculations using the program PIRK, an optical potential code, are compared to the elastic data. The results of a second set of calculations, using Glauber theory are also presented. Both sets of calculations use as input: the results of partial wave analyses of kaon nucleon scattering data, and nuclear shapes as determined from the results of electron nucleus scattering experiments. The agreement between the experimental data and the theoretical predictions is reasonable over the angular range of the data, with the exception of Glauber calculations of the K+ elastic scattering. In those cases, the eikonal approximation proves to be a poor approximation. Smaller discrepancies are found in some other cases, indicating the possible need for more sophisticated calculations
(π±, π±' N) reactions on 12C and 208Pb near the giant resonance region
Angular distributions for the 12C(π±, π±' p) and 208Pb(π±, π±' p or n) reactions near the giant resonance region have been measured at Tπ = 180 MeV, and found different between π+ and π- data. This observation is interpreted as evidence for different excitation mechanisms dominating the π--nucleus and π+-nucleus interactions in the giant resonance region of these targets. A comparison with the single-nucleon knock-out distorted-wave impulse approximation calculations shows, even though these calculations underestimate (π±, π±' N) data for both targets, the dominance of direct process for (π+, π+' p) or (π-, π-' n) in contrast to (π-, π-' p) or (π+, π+' n). In the (π+, π+' p) reaction proton-proton hole states are excited directly and appear to have a large probability for direct decay with escape width, whereas in (π-, π-' p) the preferentially excited neutron-neutron hole doorway states couple to resonance states and decay with spreading width. This interpretation led us to suggest that the ratio of cross-sections for inelastic scattering to the giant resonance region should be written in terms of an incoherent sum of cross-sections to neutron and proton doorway states. In a heavy nucleus such as 208Pb, neutron and proton doorway states. In a heavy nucleus such as 208Pb, neutron and proton doorway states contribute incoherently because the different decay processes do not populate the same final states of the residual nucleus
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.
I Ahmad; M R Arafah
2006-03-01
Elastic scattering of 800 MeV/c pions by 12C has been studied in the diffraction model with a view to determine pion optical potential by the method of inversion. Finding an earlier diffraction model analysis to be deficient in some respects, we propose a Glauber model based parametrization for the elastic -matrix and show that it provides an exceedingly good fit to the pion-carbon data. The proposed elastic -matrix gives a closed expression for the pion-12C optical potential by the method of inversion in the high energy approximation.
Quasi-elastic scattering of 6He, 7Be, and 8B nuclei by 12C nuclei
Kovalchuk, V I
2016-01-01
The observed cross sections of quasi-elastic scattering of 6He, 7Be, and 8B nuclei by 12C nuclei are described within the framework of the diffraction nuclear model and the model of nucleus-nucleus scattering in the high-energy approximation with a double folding potential, for intermediate energies of the incident particles. The calculations make use of realistic distributions of nucleon densities and take account of the Coulomb interaction and inelastic scattering with excitation of low-lying collective states of the target.
Isoscalar monopole and dipole excitations of cluster states and giant resonances in $^{12}$C
Kanada-En'yo, Yoshiko
2015-01-01
The isoscalar monopole(ISM) and dipole(ISD) excitations in $^{12}$C are theoretically investigated with the shifted antisymmetrized molecular dynamics(AMD) plus $3\\alpha$-cluster generator coordinate method(GCM). The small amplitude vibration modes are described by coherent one-particle one-hole excitations expressed by small shift of single-nucleon Gaussian wave functions within the AMD framework, whereas the large amplitude cluster modes are incorporated by superposing $3\\alpha$-cluster wave functions in the GCM. The coupling of the excitations in the intrinsic frame with the rotation and parity transformation is taken into account microscopically by the angular-momentum and parity projections. The present calculation describes the ISM and ISD excitations in a wide energy region covering cluster modes in the low-energy region and the giant resonances in the high-energy region, though the quantitative description of the high-energy part is not satisfactory. The low-energy ISM and ISD strengths of the cluster...
Nanocatalytic resonance scattering spectral analysis
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.
Local and non-local equivalent potentials for p-12C scattering
Lovell, A.; Amos, K.
2000-01-01
A Newton-Sabatier fixed energy inversion scheme has been used to equate inherently non-local p-${}^{12}$C potentials at a variety of energies to pion threshold, with exactly phase equivalent local ones. Those energy dependent local potentials then have been recast in the form of non-local Frahn-Lemmer interactions.
We measured six fairly complete angular distributions of elastic, inelastic and α-transfer reactions of the 12C+24Mg system ar Ecm = 25.2 MeV. We performed coupled channels calculations using the Algebraic Scattering Theory with nuclear algebraic potential derived from nuclear phase shifts and using available structure informations for the inelastic coupling strengths. The back angle rise in the elastic cross section is fully explained by the couplings between elastic and transfer channels. (author)
Measurement of spectra of (e,e') scattering on 9Be and 12C nuclei in inelastic region at Q22/c2
The spectra of the (e,e')-scattering on 9Be and 12C nuclei in the region of quasielastic scattering and Δ33-resonance production at angles 16 and 18 deg and primary electron energies from 1.45 GeV to 2.13 GeV are measured. A model-independent account of radiative distortions at energies 1.93 and 2.13 GeV is made. A comparison with the nuclear shell model calculations is made. The experimental data are obtained at the Erevan electron synchrotron. The background conditions are improved and the energy coverage of the set-up is enlarged by the improvement of the extraction path and pulse hodoscope of the spectrometer. 13 refs.; 5 figs
Polarized Elastic Fast-Neutron Scattering off 12C in the Lower MeV-Range. I. Experimental Part
Practical as well as more fundamental interest in low-energy n-12C elastic scattering motivated the execution of comprehensive polarization studies between 1.062 and 2.243 MeV. Seven complete polarization angular distributions were obtained from experimental finite-geometry left-right ratios at each energy observed at six or seven laboratory scattering angles between 30 and 129 deg, using polarized fast-neutrons emitted at θi 50 (lab. syst.) from the 7Li(p, n) 7Be-reaction. Proper corrections were applied for finite geometry and polarized multiple-scattering effects as well as for the presence of the first-excited state group of fast-neutrons in the incident beams. The magnitude of the polarization effects are sufficiently large to ensure the potentialities of 12C as an acceptable fast-neutron polarization analyser in the energy range under consideration. Furthermore, on the basis of the above-mentioned polarization data as well as on the basis of total and differential scattering cross section data available in current literature reliable phase shifts were determined. These phase shifts are only in partial agreement with the ones of Wills, Jr. et al. , and in definite disagreement with the extrapolated phases of Meier, Scherrer, and Trumpy. Their energy variations will be predicted in the theoretical part of this contribution
Measurement of quasi-elastic 12C(p,2p) scattering at high momentum transfer
Mardor, Y.; Aclander, J.; Alster, J.; Barton, D; Bunce, G.; Carroll, A.; Christensen, N.; Courant, H.; Durrant, S.; Gushue, S.; Heppelmann, S.; Kosonovsky, E.; Mardor, I.; Marshak, M.; Makdisi, Y.
1997-01-01
We measured the high-momentum quasi-elastic 12C(p,2p) reaction (at center of mass angle near 90 degrees) for 6 and 7.5 GeV/c incident protons. The three-momentum components of both final state protons were measured and the missing energy and momentum of the target proton in the nucleus were determined. The validity of the quasi-elastic picture was verified up to Fermi momenta of about 450 MeV/c, where it might be questionable. Transverse and longitudinal Fermi momentum distributions of the ta...
A fully microscopic model of 200 MeV proton-{sup 12}C elastic and inelastic scattering
Karataglidis, S.; Dortmans, P.J.; Amos, K.; de Swiniarski, R.
1996-03-01
An effective two nucleon (NN) interaction in the nuclear medium is defined from an accurate mapping of the NN g matrices obtained by solving the Brueckner-Bethe-Goldstone equations for infinite nuclear matter. That effective interaction is used in a fully microscopic calculation of the nonlocal effective proton-{sup 12}C interaction from which are obtained predictions of the differential cross section and analysing power for 200 MeV elastic scattering. The relative motion wave functions so found are used as the distorted waves in a distorted wave approximation (DWA) study of select inelastic scattering events. The effective NN interaction is used as the transition operator in those calculations. The relevant nuclear spectroscopy for the elastic and DWA (p, p`) calculations is found from a full (0 + 2) {Dirac_h}{omega} shell model evaluation of the positive parity states while a restricted (1 + 3){Dirac_h}{omega} has been used to give the negative parity states. Results are compared with those of the 0p-shell model of Cohen and Kurath or with those based upon axially symmetric, projected Hartree-Fock calculations. The diverse structure model wave functions are assessed by using them in calculations to compare with measured longitudinal, transverse electric and transverse magnetic form factors from electron scattering to many of the excited states of {sup 12}C. Using those models of the structure of {sup 12}C in the completely microscopic model of the elastic and inelastic scattering of 200 MeV protons, good fits have been found to the cross section and analysing power data. 50 refs., 3 tabs., 20 figs.
Elastic scattering of intermediate energy protons on 4He and 12C
The elastic angular distribution and polarization of 1.04 GeV protons on 4He and 12C have been analysed using the recently proposed correlated expansion for the Glauber amplitude by retaining terms up to three-body density only. The calculations include Coulomb and spin effects. Using realistic form factors for target nuclei it is found that we need to consider only up to the second-order density term to provide a satisfactory explanation of both kinds of experimental data in the available momentum transfer region. The contribution of the three-body density term is only marginal except in 4He differential cross-section in the c.m. angular range 4500. (author)
Neutron scattering from 12C in the few-MeV region
Neutron total cross sections of natural carbon are deduced from the observed transmission of approximately monoenergetic neutrons through carbon samples of varying thickness. The measurements extend from approximately equal to 0.1 to 4.5 MeV with resolutions of approximately equal to 2 to 100 keV. Neutron differential-elastic-scattering cross sections of natural carbon are measured from 1.5 to 4.0 MeV at incident-neutron energy intervals of approximately less than 100 keV, over an angular range of approximately equal to 20 to 1600 and with energy resolutions of 20 to 50 keV. The experimental results are interpreted in terms of a multilevel R-function analysis. Results are compared with the large body of measured and evaluated neutron total and scattering cross sections and scattered neutron polarizations reported in the literature. It is suggested that the observed neutron total and scattering cross sections of carbon are physically consistent and suitable for use as a reference standard in experimental studies of neutron processes. The R-function description should provide a convenient description of neutron total and scattering cross sections of carbon as a function of both angle and energy. 88 references
Well-verified models for elastic and inelastic scattering of fast neutrons (and protons) from 12C and 16O are translated into a useful form for transport, dosimetry, and scintillator response calculations. The information presented here is complementary to published calculations of secondary-particle production by incident neutrons in the energy region 15 ≤ En ≤ 60 MeV. Tables are given of Legendre expansion coefficients derived from fits to experimental cross sections at incident neutron energies En = 18-26 MeV and from fits to model predictions for 30- to 60-MeV neutrons. 11 refs., 8 tabs
{sup 16}O resonances near 4α threshold through {sup 12}C({sup 6}Li,d) reaction
Rodrigues, M. R. D.; Borello-Lewin, T.; Miyake, H.; Horodynski-Matsushigue, L. B.; Duarte, J. L. M.; Rodrigues, C. L.; Faria, P. Neto de [Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, CEP 05314-970, São Paulo, SP (Brazil); Cunsolo, A.; Cappuzzello, F.; Foti, A.; Agodi, C.; Cavallaro, M. [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Napoli, M. di; Ukita, G. M. [Faculdade de Psicologia, Universidade de Santo Amaro, R. Prof. Eneas da Siqueira Neto, 340, CEP 04829-300, São Paulo, SP (Brazil)
2014-11-11
Several narrow alpha resonant {sup 16}O states were detected through the {sup 12}C({sup 6}Li,d) reaction, in the range of 13.5 to 17.5 MeV of excitation energy. The reaction was measured at a bombarding energy of 25.5 MeV employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion technique. Experimental angular distributions associated with natural parity quasi-bound states around the 4α threshold are presented and compared to DWBA predictions. The upper limit for the resonance widths obtained is near the energy resolution (15 keV)
Couture, Aaron Joseph [Los Alamos National Laboratory; Detwiler, Rebecca [UNIV OF FL; Gorres, Joachim [UNIV OF NOTRE DAME; Stech, Edward J [UNIV OF NOTRE DAME; Ugalde, Claudio [UNIV OF NOTRE DAME; Wiescher, Michael C F [UNIV OF NOTRE DAME; Heil, Michael [GSI DARMSTADT; Kappeler, Franz [FORSCHUNGSZENTRUM KARLSRUHE; Azuma, Richard E [UNIV OF TORONTO; Buchmann, Lothar [TRIUMF
2009-01-01
Recent global analyses of {sup 12}C({alpha},{gamma}){sup 16}O have incorporated both elastic-scallering and {beta}-decay data in addition to direct measurements. In that context, it has been shown that an improvement in the available elastic-scallering data could help determine the contribution of the two subthreshold states, 6.92(2{sup +}) and 7.12(1{sup -}) MeV, and with excellent statistics could restrict resonance parameters above the threshold. To this end angular distributions of {sup 12}C({alpha}, {alpha}){sup 12}C in the {alpha}-energy range of 2.6-8.2 MeV, at angles from 24 to 166 have been measured at the University of Notre Dame using an array of 32 silicon detectors. Details of the experiment are reported. In the present analysis, the phase shifts have been determined from our previously reported R-matrix fit to these data. The uncertainties in the R-matrix phase shifts ({ell} = 0...6) are derived by a new Monte Carlo analysis technique as described in the article. We provide these phase shifts here for general use, in particular for the improved analysis and extrapolation of the {alpha} radiative capture to low energies.
The detailed study of the pion-nucleus scattering in the range of the Δ(3.3) resonance permits statements on the behaviour of a strong resonance in the surrounding nuclear medium and raises by this the question for the importance of subnuclear degrees of freedom in the nucleus. In the present thesis the pion-nucleus reaction mechanism was studied by means of pion-γ-angular correlation measurements on the 12C(2+, 4.4 MeV) state. The experiments were performed at the Swiss Institute for Nuclear Research. The scattered pions were detected by the SUSI spectrometer to which in coincidence six NaI detectors for the detection of the emitted γ-quanta were operated. For the momentum transfer q = 0.47 fm-1 and pion incident energies of 116, 140, 162, 180, and 226 MeV respectively for the momentum transfer q = 0.85 fm-1 and incident energies of 116, 162, and 226 MeV values of the angular correlation function for in the mean each 16 γ emission angles within and beyond the reaction plane were determined. The measurement results are compared with DWIA calculations in the static limit and in the Δ-hole model. In the static limit the transition is described starting from the free pion-nucleon process whereby the dynamics of the intermediate Δ-resonance are suppressed. The Δ-hole model yields an additional microscopical description for the propagation of the Δ-resonance. The static model cannot reproduce the energy slope of the correlation function for q = 0.47 fm-1 while the Δ-hole model achieves a very good agreement. The experiment shows by this that the description of the pion-nucleus scattering in the resonance range requires the regard of medium effects especially from the Δ propagation. (orig.)
Quasi-free scattering off 12C in inverse kinematics at the R3B/LAND-setup
An important part of the physics program at the future R3B (Reactions with Relativistic Radioactive Beams) experiment at FAIR will be based on the study of proton-induced reactions in a kinematical complete measurement. These are in particular the quasi-free scattering processes of the type (p,2p), (p,pn), (p,pα) etc, which will be used to investigate the single-particle and cluster structure of neutron-proton asymmetric nuclei and the role of nucleon-nucleon correlations in nuclei. A prototype setup for the detection of high-energy protons in (p,2p) reactions in coincidence with forward emitted light particles and heavy fragments has been built based on an array of Si micro-strip detectors for tracking and thick NaI scintillators for energy measurements. A 12C beam has been chosen for the bench-mark experiment since its structure is well known, and results from proton- as well as electron-induced knockout reactions are available. First results on two-proton angular correlations and momentum distributions of the knocked-out protons inside 12C are discussed as well as the excitation energy spectrum of the residual 11B nuclei.
Elastic and inelastic scattering of 400 MeV polarised deuterons on 12C, 24Mg, 40Ca nuclei
This research thesis is based on an experiment of scattering of polarised 400 MeV deuterons on 12C, 24Mg, 40Ca nuclei, performed on the Saturne accelerator. The measured observables are the non-polarised cross section, and the powers of vector and tensor analysis. The author describes the experiment running and the installation, presents the various devices from source to detection and acquisition by the computer system. He reports the experiment compilation: reading of magnetic tapes, assessment and taking into account of the different experimental parameters. The calculation of scattering observables (cross section and powers of analysis) is performed by using experimental data. Spectra of these observables are represented for the different excited states of nuclei, after, should the occasion arise, Gaussian decomposition or background subtraction. The author reports the analysis of the obtained results. Results obtained for the three nuclei are compared between each other, and with scattering data for protons at similar energies which have already been measured. An analysis with a microscopic model is performed and the predictions of this model are compared with the obtained results
Hassanain, Mahmoud A. [King Khalid University, Department of Physics, Abha (Saudi Arabia); Assiut University, Department of Physics, New-Valley Faculty of Science, Assiut (Egypt)
2016-01-15
Differential cross-section of the {sup 16}O+{sup 12}C elastic scattering at E{sub lab} = 132, 181, 200, 260, 300, 608 and 1503MeV has been reanalyzed in the framework of double-folding cluster (DFC1) potential over a wide angular range which cover both diffractive and refractive regions. Based upon the α-cluster structure of both colliding nuclei, the real DFC1 optical potential has been generated by using α-α effective interaction and new cluster modified Gaussian (CMGD) of target and projectile has also been extracted. Successful descriptions of the data were obtained over the full measured angular range at all considered energies. The results have been compared with the findings obtained by using the phenomenological approach as well as experimental data. Furthermore, the consistency between the real and imaginary volume integrals is checked by the dispersion relation and the total reaction cross-section has also been investigated. (orig.)
Isotopic 13C/12C effect on the resonant Raman spectrum of twisted bilayer graphene
del Corro, E.; Kalbáč, Martin; Fantini, C.; Frank, Otakar; Pimenta, M. A.
2013-01-01
Roč. 88, č. 15 (2013), s. 155436. ISSN 1098-0121 R&D Projects: GA MŠk LL1301 Institutional support: RVO:61388955 Keywords : substrate * spectroscopy * scattering Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.664, year: 2013
Hamada, Sh; Burtebayev, N; Ohkubo, S
2013-01-01
Angular distributions for elastic and inelastic scattering of $^3$He from $^{12}$C were measured at energies 50.5 and 60 MeV. The Airy minimum of the prerainbow scattering was clearly observed in the angular distributions for the 0$_2^+$ (7.65 MeV) state of $^{12}$C (Hoyle state). The experimental results were analyzed with a coupled channels method with double folding potentials derived from the microscopic wave functions for the ground 0$_1^+$, 2$^+$ (4.44 MeV), 3$^-$ (9.64 MeV) and 0$_2^+$ states. The analysis supports the view that the Hoyle state is a three alpha particle condensate with a large radius of dilute matter distribution.
The triple alpha reaction rate and the 2$^+$ resonances in $^{12}$C
de Diego, R; Fedorov, D V; ~Jensen, A S
2010-01-01
The triple alpha rate is obtained from the three-body bound and continuum states computed in a large box. The results from this genuine full three-body calculation are compared with standard reference rates obtained by two sequential two-body processes. The fairly good agreement relies on two different assumptions about the lowest $2^+$ resonance energy. With the same $2^+$ energy the rates from the full three-body calculation are smaller than those of the standard reference. We discuss the rate dependence on the experimentally unknown $2^+$ energy. Substantial deviations from previous results appear for temperatures above $3$~GK.
Reinhardt, Tobias P; Bemmerer, Daniel; Stöckel, Klaus; Wagner, Louis
2016-01-01
Resonant nuclear reactions are a powerful tool for the determination of the amount and profile of hydrogen in thin layers of material. Usually, this tool requires the use of a standard of well-known composition. The present work, by contrast, deals with standard-less hydrogen depth profiling. This approach requires precise nuclear data, e.g. on the widely used $^{1}$H($^{15}$N,$\\alpha\\gamma$)$^{12}$C reaction, resonant at 6.4\\,MeV $^{15}$N beam energy. Here, the strongly anisotropic angular distribution of the emitted $\\gamma$-rays from this resonance has been re-measured, resolving a previous discrepancy. Coefficients of (0.38$\\pm$0.04) and (0.80$\\pm$0.04) have been deduced for the second and fourth order Legendre polynomials, respectively. In addition, the resonance strength has been re-evaluated to (25.0$\\pm$1.5)\\,eV, 10\\% higher than previously reported. A simple working formula for the hydrogen concentration is given for cases with known $\\gamma$-ray detection efficiency. Finally, the absolute approach i...
Absolute hydrogen depth profiling using the resonant 1H(15N, αγ)12C nuclear reaction
Reinhardt, Tobias P.; Akhmadaliev, Shavkat; Bemmerer, Daniel; Stöckel, Klaus; Wagner, Louis
2016-08-01
Resonant nuclear reactions are a powerful tool for the determination of the amount and profile of hydrogen in thin layers of material. Usually, this tool requires the use of a standard of well-known composition. The present work, by contrast, deals with standard-less hydrogen depth profiling. This approach requires precise nuclear data, e.g. on the widely used 1 H(15 N, αγ)12 C reaction, resonant at 6.4 MeV 15 N beam energy. Here, the strongly anisotropic angular distribution of the emitted γ -rays from this resonance has been re-measured, resolving a previous discrepancy. Coefficients of (0.38 ± 0.04) and (0.80 ± 0.04) have been deduced for the second and fourth order Legendre polynomials, respectively. In addition, the resonance strength has been re-evaluated to (25.0 ± 1.5) eV, 10% higher than previously reported. A simple working formula for the hydrogen concentration is given for cases with known γ -ray detection efficiency. Finally, the absolute approach is illustrated using two examples.
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.
Systematic study on nuclear resonant scattering
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
Hamada, Sh; Burtebayev, N [Kazakh National University, Almaty (Kazakhstan); Gridnev, K A [St Petersburg University, St Petersburg (Russian Federation); Amangeldi, N, E-mail: Sh.m.hamada@gmail.com [Eurasia National University, Astana (Kazakhstan)
2011-10-15
The angular distribution for the elastic scattering of {sup 16}O, {sup 14}N and {sup 12}C on {sup 27}Al was measured at an energy of 1.75 MeV per nucleon in the DC-60 INP NNC (Institute of Nuclear Physics, National Nuclear Centre) cyclotron located in Astana in order to study the elastic scattering mechanism in these nuclear systems. The experimental results were analyzed with the help of the optical potential code SPI-GENOA. Good agreement between the experimental data and the theoretical calculations was obtained by using suitable optical potential parameters. The elastic scattering of {sup 16}O, {sup 14}N and {sup 12}C on {sup 27}Al does not reveal any unusual features or threshold anomaly at this energy.
The angular distribution for the elastic scattering of 16O, 14N and 12C on 27Al was measured at an energy of 1.75 MeV per nucleon in the DC-60 INP NNC (Institute of Nuclear Physics, National Nuclear Centre) cyclotron located in Astana in order to study the elastic scattering mechanism in these nuclear systems. The experimental results were analyzed with the help of the optical potential code SPI-GENOA. Good agreement between the experimental data and the theoretical calculations was obtained by using suitable optical potential parameters. The elastic scattering of 16O, 14N and 12C on 27Al does not reveal any unusual features or threshold anomaly at this energy.
Resonances in Positron-Mg Scattering
PENG Yue; CHENG Cheng; ZHOU Ya-Jun
2007-01-01
We present the results for resonances in positron-Mg scattering at low impact energy (0-5.0eV) by using the momentum space coupled-channel optical (CCO) method in momentum space. The S-partial wave resonance at 3.880eV, P-partial wave resonance at 4.020eV, and D-partial wave resonance at 4.267eV are found.
The Ohio University Beam Swinger provides a high resolution, low back-ground time-of-flight facility for the measurement of elastic and inelastic neutron scattering. It has been used to obtain a comprehensive set of differential scattering cross sections for 12C, 14N, 16O and 40Ca between 18 and 26 MeV. The elastic cross sections can be used directly to obtain partial kerma factors and, combined with the known total cross sections, provide accurate values for the reaction cross sections. Angular distributions have been measured for inelastic scattering from all the nuclear levels that cannot decay by particle emission thus providing (by subtraction) a limit on the sum of all charged-particle producing reactions. The integrated cross sections for inelastic scattering from some particle-unstable states in 12C are in excellent agreement with the cross sections for three-body breakup obtained by Antolkovic et al. The differential data have been used, together with higher energy proton scattering data to produce energy-dependent optical model parameters for each of these nuclei in the energy range 20-60 MeV. It has been found that the elastic differential cross sections at theta > 1000 for 12C, 14N and 16O cannot be well described by a spherical optical model. Explicit consideration of coupled-channel effects, and in the case of 12C, deformation of the ground state, improves the agreement between calculation and experiment. Heavy ion recoil kerma factors and reaction cross sections have been obtained for each element and compared with previous calculations and measurements
Wilson, David J. [Old Dominion University, Norfolk, VA
2014-06-23
We have obtained clear signals of resonances in coupled-channel pi K - eta K scattering. Using distillation and a large basis of operators we are able to extract a precise spectrum of energy levels using the variational method. These energies are analysed using inelastic extensions of the Luescher method to obtain scattering amplitudes that clearly describe S, P and D wave resonances, corresponding to the physical K_0^*(1430), the K^*(892) and the K_2^*(1430).
Resonant electron scattering by graphene antidot
Zagorodnev, I. V.; Devizorova, Zh. A.; Enaldiev, V. V.
2015-01-01
The edge states which were observed on a linear edge of graphene may also persist on a curved edge. We calculate the elastic transport scattering cross section on a graphene nanohole supporting the edge states. Resonant peaks in the gate voltage dependence of conductivity of graphene with such nanoholes are obtained. Position and height of the resonances are determined by the localization depth of the quasibound edge states, and width -- by their lifetime. The scattering amplitude near the re...
Medium modified effective two nucleon interactions are defined for protons incident upon 12C with energies in the range 200 to 800 MeV. Those effective interactions have been folded with the ground state density to specify nonlocal optical potentials that were then used to analyse the elastic scattering differential cross sections and analysing powers. A select set of isoscalar and isovector, positive and negative parity, inelastic proton scattering transitions have also been analysed using the same (microscopic) optical models to define the distorted wave functions needed in Distorted Wave Approximation calculations of the associated differential cross sections and analysing powers. All results are compared with ones found using the Love-Franey effective interactions. The nuclear structure relating to these transitions was chosen from (0+2) ℎω and (1+3)ℎω shell model calculations of the positive and negative parity spectra of 12C respectively. 21 refs., 12 figs
Measurements of the neutron scattering cross sections for 12C, 16O, 40Ca and 56Fe at 14.2 MeV
Double different cross sections and energy-integrated differential ones for elastic and inelastic scattering from 12C, 16O, 40Ca, and 56Fe at 14.2 MeV have been measured at forward angles from 10O to 70O in 10O steps. The experimental data have been compared with the predictions of JENDL-3 as well as those of optical model and DWBA calculations. (author)
We investigated the in-medium effect by density-dependent axial and weak-vector form factors on muon-neutrino (νμ) and anti-muon-neutrino ( ν-bar μ) scattering in the quasi-elastic (QE) region from nucleons (N*) bound in a nucleus or immersed in a nuclear medium via neutral current (NC) and charged current (CC). For the density-dependent form factors, we exploited a quark–meson-coupling (QMC) model. We found that the νμ( ν-bar μ)−N∗ scattering cross sections via NC in the QE region usually decrease with an increased medium density, while those using CC were increased. However, their rate of change was sensitive to the four-momentum transfer given to a bound nucleon through scattering. We compared these results obtained by the elementary process corrected by the in-medium effect to the BNL and MiniBooNE data, which measured νμ scattering cross sections per nucleon through νμ – 12C scattering in 12C composite targets. The incident energy range was 550 ν12C, we exploited the QMC form factors evaluated at ρ=0.5ρo, where the normal density ρo∼0.15 fm−3. The strangeness contributions in NC scattering are also incorporated into the form factors for comparison with experimental data. Our numerical results show that most of the experimental data can be explained in a satisfactory manner by the density-dependent elementary process, but there are some remaining deviations resulting from the nuclear structure, particularly in the low and high momentum-transfer regions. (paper)
Resonances in Positron-He Scattering
XIAO Dan; JIANG Ping-Hui; ZHOU Ya-Jun
2007-01-01
We present the results for resonances in positron-He scattering at low impact energy (19.3-24.0eV) by using the momentum space coupled-channel optical (CCO) method. The S-partial wave resonance at 20.16eV is found for the first time.
Multi-cluster problems: resonances, scattering and condensed states
This talk is mainly concerned with many-body resonances in nuclear physics. We extensively discuss the structure and reactions of multi-cluster systems using the complex scaling method (CSM). We expound three interesting problems in recent studies of multi-cluster systems. First, we discuss four- and five-body resonances in A=7 (7He, 7B) and A=8 (8He, 8C) systems, respectively. The observed states are well explained and many additional states are predicted. Second, the Coulomb breakup reactions of two-neutron halo nuclei and the α-d scattering are investigated using a three-body model with CSM. Finally, we discuss the α-condensate-like states and their symplectic excitation properties in three- and four-α models for 12C and 16O, respectively.
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
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.
A note on the use/determination of relative alpha scattering phases in the 12C(α,γ)16O reaction
A new experiment to determine the thermonuclear cross section of the 12C(α,γ)16O reaction has been performed in regular kinematics using an intense α-particle beam. In this experiment a 4π-detector setup has been used for the first time to measure all angles of each γ-angular distribution simultaneously. The 12C targets were isotopically enriched by magnetic separation during implantation. The depth profiles of the implanted carbon in the 12C targets have been determined by Rutherford backscattering for purposes of cross section normalization and absolute determination of the E1- and E2-S-factors. Angular distributions have been measured. From these distributions, astrophysical E1- and E2-S-factor functions vs. energy have been calculated, both of which are indispensable for modelling of this reaction and the extrapolation towards lower energies. The separation of the E1- and E2-S-capture channels has been done both by taking the phase value φ12 as a free parameter and by fixing it using the results of elastic α-particle scattering on 12C in the same energy range. The precision and accuracy of these new measurements make it possible to distinguish between the two methods of analysis. Preliminary values of S-factors extrapolated to 300 keV will be presented. (author)
Csedreki, L., E-mail: csedreki@atomki.mta.hu [Institute for Nuclear Research, Hungarian Academy of Sciences, MTA Atomki, H-4001 Debrecen, P.O. Box 51 (Hungary); Szíki, G.Á. [University of Debrecen, Faculty of Engineering, Department of Basic Technical Studies, H-4028 Debrecen, Ótemető u. 2-4 (Hungary); Szikszai, Z. [Institute for Nuclear Research, Hungarian Academy of Sciences, MTA Atomki, H-4001 Debrecen, P.O. Box 51 (Hungary); Kocsis, I. [University of Debrecen, Faculty of Engineering, Department of Basic Technical Studies, H-4028 Debrecen, Ótemető u. 2-4 (Hungary)
2015-01-01
The observed resonance parameters of the {sup 12}C(d,pγ){sup 13}C reaction in the vicinity of 1450 keV deuteron energy have been determined in a thorough procedure, fitting our recent experimental excitation curve, as well as earlier literature data with the Root Software Package. The resulting energy and width (FWHM) of resonance are 1445.8 ± 0.2 keV and 5.3 ± 0.4 keV, respectively. We propose the application of this resonance as a precise and simple method for accelerator energy calibration when performing DIGE analysis.
Bystritsky, V. M.; Grozdanov, D. N.; Zontikov, A. O.; Kopach, Yu. N.; Rogov, Yu. N.; Ruskov, I. N.; Sadovsky, A. B.; Skoy, V. R.; Barmakov, Yu. N.; Bogolyubov, E. P.; Ryzhkov, V. I.; Yurkov, D. I.
2016-07-01
The work is devoted to measuring the angular distribution of 4.43-MeV γ-rays produced in inelastic scattering of 14.1-MeV neutrons by 12C nuclei. A portable ING-27 neutron generator (designed and fabricated at VNIIA, Moscow) with a built-in 64-pixel silicon α-detector was used as a source of tagged neutrons. The γ-rays of characteristic nuclear radiation from 12C were detected with a spectrometric system that consisted of 22 γ-detectors based on NaI(Tl) crystals arranged around the carbon target. The measured angular distribution of 4.43-MeV γ-rays is analyzed and compared with the results of other published experimental works.
Elastic scattering for 16O + 12C at 140 MeV and 218 MeV
In this work, angular distribution of cross sections have been measured for 12C(16O,16O)12C at two energies. The measurements were carried out in 0.50 intervals between 50-19.50C (lab.) at 140 MeV, 4.50-14.50 at 218 MeV. An optical model analysis of these strong structure angular distributions was done. Good fits of the data were obtained using the optical model search code GENOA with a full Woods-Saxon potential form. This yielded parameters subject to considerable ambiguities as it is known to occur for strongly absorbed particles. These ambiguities were explored in detail and it was found that both the real and the imaginary parts present some characteristics that have been found before for the real potential (as Igo relation for continous ambiguities and the fact that potentials with different diffusivities tend to have the same value at the strong absorption radii). It was found, among other results, that the real volume integral, the mean square radius, as well as the total reaction cross section (σsub(r)) cannot be determined unambiguously. A strong correlation was found between σsub(r) and the imaginary diffusivity. A systematic study of how the variation of the potential parameters affects the angular distribution is presented and some features of the diffraction structure of the angular distribution are discussed. (author)
Inelastic scattering in resonant tunneling
Wingreen, Ned S.; Jacobsen, Karsten Wedel; Wilkins, John W.
1989-01-01
The exact resonant-tunneling transmission probability for an electron interacting with phonons is presented in the limit that the elastic coupling to the leads is independent of energy. The phonons produce transmission sidebands but do not affect the integrated transmission probability or the...
Resonance scattering spectroscopy of gold nanoparticle
JIANG; Zhiliang; FENG; Zhongwei; LI; Tingsheng; LI; Fang; ZHONG; Fuxin; XIE; Jiyun; YI; Xianghui
2001-01-01
The gold nanoparticles in diameter of 10-95 nm have been prepared by Frens procedure, all of which exhibit a resonance scattering peak at 580 nm. The mechanism of resonance scattering for gold nanoparticle has been considered according to the wave motion theory of nanoparticle in liquid. The principle of superamolecular interface energy band(SIEB) has been set up and utilized to explain the relationship between the diameter and colors for gold nanoparticle in liquid. A novel spectrophotometric ruler for the determination of the diameter has been proposed according to the relationship of the maximum absorption wavelength and diameter.
Scattering by coupled resonating elements in air
Krynkin, Anton; Chong, Alvin Y B; Taherzadeh, Shahram; Attenborough, Keith
2011-01-01
Scattering by (a) a single composite scatterer consisting of a concentric arrangement of an outer N-slit rigid cylinder and an inner cylinder which is either rigid or in the form of a thin elastic shell and (b) by a finite periodic array of these scatterers in air has been investigated analytically and through laboratory experiments. The composite scatterer forms a system of coupled resonators and gives rise to multiple low frequency resonances. The corresponding analytical model employs polar angle dependent boundary conditions on the surface of the N-slit cylinder. The solution inside the slits assumes plane waves. It is shown also that in the low-frequency range the N-slit rigid cylinder can be replaced by an equivalent fluid layer. Further approximations suggest a simple square root dependence of the resonant frequencies on the number of slits and this is confirmed by data. The observed resonant phenomena are associated with Helmholtz-like behaviour of the resonator for which the radius and width of the o...
A Survey of Beam Asymmetries in Semi-exclusive Electron Scattering on {sup 4}He and {sup 12}C
Dan Protopopescu
2002-12-01
A study of the polarized electron beam asymmetry in semi-exclusive (e,e{prime}p) reactions on {sup 4}He and {sup 12}C over a large kinematic range has been performed. The beam asymmetry A{prime}{sub LT} is related to the imaginary part of the longitudinal-transverse interference and therefore it vanishes in reactions proceeding through a channel with a single dominant mechanism. In quasifree nucleon knockout, the helicity asymmetry provides an unambiguous signature for the interference between direct knockout and rescattering amplitudes. The data were taken in April-May 1999 using polarized beams of energies between 2.2 and 4.4 GeV, with the CEBAF Large Acceptance Spectrometer (CLAS) detector located in Hall B at the Jefferson Laboratory, VA. The measured asymmetries compare well with the theoretical predictions.
Resonance strengths in the 14N(p,gamma)15O and 15N(p,alpha gamma)12C reactions
Marta, Michele; Bemmerer, Daniel; Beyer, Roland; Broggini, Carlo; Caciolli, Antonio; Erhard, Martin; Fülöp, Zsolt; Grosse, Eckart; Gyürky, György; Hannaske, Roland; Junghans, Arnd R; Menegazzo, Roberto; Nair, Chithra; Schwengner, Ronald; Szücs, Tamás; Vezzú, Simone; Wagner, Andreas; Yakorev, Dmitry
2010-01-01
The 14N(p,gamma)15O reaction is the slowest reaction of the carbon-nitrogen-oxygen cycle of hydrogen burning in stars. As a consequence, it determines the rate of the cycle. The 15N(p,alpha gamma)12C reaction is frequently used in inverse kinematics for hydrogen depth profiling in materials. The 14N(p,gamma)15O and 15N(p,alpha gamma)12C reactions have been studied simultaneously, using titanium nitride targets of natural isotopic composition and a proton beam. The strengths of the resonances at Ep = 1058 keV in 14N(p,gamma)15O and at Ep = 897 and 430 keV in 15N(p,alpha gamma)12C have been determined with improved precision, relative to the well-known resonance at Ep = 278 keV in 14N(p,gamma)15O. The new recommended values are \\omega\\gamma = 0.352$\\pm$0.018, 362$\\pm$20, and 22.0$\\pm$0.9\\,eV for their respective strengths. In addition, the branching ratios for the decay of the Ep = 1058 keV resonance in 14N(p,gamma)15O have been redetermined. The data reported here should facilitate future studies of off-resona...
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...
Murata, Toru [AITEL Corp., Tokyo (Japan)
1998-03-01
The {sup 12}C({alpha},n){sup 15}O reaction and the {sup 13}C({alpha},n){sup 16}O reaction were analyzed with a resonance formula in the incident {alpha}-particle energy range of 1.0 to 16.0 MeV. With the obtained resonance parameters, branching ratios of the emitted neutrons to the several levels of the residual nucleus and their angular distributions were calculated to obtain the energy spectrum of emitted neutrons. Thick target neutron yield of carbon were also calculated and compared with the experimental data. (author)
Resonant elastic scattering, inelastic scattering and astrophysical reactions
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)
Resonances in the proton-6Li scattering
The differential cross section and the analyzing power of the p+6Li scattering were measured in the laboratory energy range from 1.6 respectively 2.8 MeV to 10 MeV at 45 respectively 40 energies in full angular distributions. The data were subjected both to an analysis in the optical model which yielded already hints to resonance effects and to a comphrehensive scattering-phase analysis for L=0, 1, and 2 under inclusion of channel spin and orbital angular momentum mixings. The consistent description of all data required the assumption of broad resonance structures. An approximate parametrization by a Breit-Wigner formula allowed the estimation of the resonance parameters. (orig./HSI)
Mean-field study of $^{12}$C+$^{12}$C fusion
Chien, Le Hoang; Khoa, Dao T
2016-01-01
The nuclear mean-field potential arising from the $^{12}$C+$^{12}$C interaction at the low energies relevant for the astrophysical carbon burning process has been constructed within the double-folding model, using the realistic nuclear ground-state density of the $^{12}$C nucleus and the effective M3Y nucleon-nucleon (NN) interaction constructed from the G-matrix of the Paris (free) NN potential. To explore the nuclear medium effect, both the original density independent M3Y-Paris interaction and its density dependent CDM3Y6 version have been used in the folding model calculation of the $^{12}$C+$^{12}$C potential. The folded potentials at the different energies were used in the optical model description of the elastic $^{12}$C+$^{12}$C scattering at the energies around and below the Coulomb barrier, as well as in the barrier penetration model to estimate the fusion cross section and astrophysical $S$ factor of the $^{12}$C+$^{12}$C reactions at the low energies. The obtained results are in good agreement wit...
Nondestructive assay using nuclear resonance fluorescence scattering
Nondestructive assay using Nuclear resonance fluorescence (NRF) with a laser Compton scattering (LCS) gamma-ray beam is considered to be useful method to measure Pu-239 inside of a spent nuclear fuel and a melted fuel. We have proposed some detection methods coupled with NRF. One of them is the measuring the scattering gamma-ray from the target. In this method, the various background increases the statistical error of the measured quantity of Pu-239. We discuss the statistical precise with a function of the energy of the incident LCS gamma-ray. (author)
Resonance scattering in quantum wells with nanocenters
Satanin, A M
2002-01-01
The study on the Fano resonances is carried out in the 2D systems and their contribution to the residual resistance is calculated. The quantum well, the states whereof interfere with the nanocenters, for example, with the delta-layer donor states or with the quantum points states, is considered as a model. It is shown, that the states, localized on the state centers, lead to the appearance of additional asymmetric peaks in the resistance dependence on the Fermi energy. It is also shown, that the finite radius nanocenters in the 2D electron layers may lead to origination of the Fano resonances in the scattering cross section
Resonances in photon-photon scattering
A quantity called stickiness is introduced which should be largest for J not equal to 0 glueballs and can be measured in two photon scattering and radiative J/psi decay. An argument is reviewed suggesting that light J = 0 glueballs may have large couplings to two photons. The analysis of radiative decays of eta and eta' is reviewed and a plea made to desist from false claims that they are related to GAMMA(π0 → γγ) by SU(3) symmetry. It is shown that two photon studies can refute the difficult-to-refute hypothesis that xi(2220) or zeta(8320) are Higgs bosons. A gallery of rogue resonances and resonance candidates is presented which would usefully be studied in γγ scattering, including especially the low mass dipion. 34 references
The nuclear burning process proceeds from the conservation of the most abundant element hydrogen to helium, then from helium to carbon and oxygen, and then from these to heavier elements. Some of the key reactions for the carbon and oxygen burning stages of the nucleosynthesis are 12C+12C and 16O+16O leading to all possible final states. This paper contains the experimental measurements of 12C+12C and 16O+16O angular distributions performed at the cyclotron DC-60 in Astana, Kazakhstan. The extracted beam of 16O and 12C was accelerated up to two energies 1.75 and 1.5 MeV/n and then directed to an Al2O3 target of thickness 20 μg/cm2 and a carbon self-supporting target of thickness 17.4 μg/cm2. The angular distribution calculations were performed using both the phenomenological optical potential (SPI-GENOA) code and the double folding potential (FRESCO) code.
Fano resonances in scattering: an alternative perspective
The characteristic features of Fano resonances (also called Feshbach resonances in nuclear physics) are asymmetric line shapes, caused by the interaction between a discrete state and a continuum of states. In a previous paper it has been shown that the interference of the first and second order pole of the Green's function at an exceptional point, as well as the interference of the first order poles in the vicinity of the exceptional point, gives rise to asymmetric scattering cross section profiles. In the present paper we demonstrate that these line profiles are indeed well described by the Beutler-Fano formula, and thus are genuine Fano resonances. Also further away from the exceptional points excellent agreement can be found by introducing energy dependent Fano parameters
Elastic and inelastic scattering studies for the systems 12C+28Si and 16O+/sup 28,29,30/Si
Elastic and inelastic excitation functions for the systems 12C+ 28Si and 16O+/sup 28,29,30/Si have been measured at theta/sub c.m./ = 1800 from the Coulomb barrier up to E/sub c.m./ = 45 MeV (12C+28Si), E/sub c.m./ = 52 MeV (16O+28Si), and E/sub c.m./ = 32 MeV (16O+/sup 29,30/Si). Over the whole energy range they all exhibit pronounced and regular broad oscillations (0.50 were taken at five of the maxima and near a minimum of the excitation function for the system 16O+28Si. All angular distributions are oscillatory and exhibit a strong backward rise. The data are discussed in terms of a coherent superposition of a background and a resonant amplitude and in terms of the interference between the internal and barrier wave reflected by a deep optical potential
Cook, J.; Clarice, N. M.; Coopersmith, J.; Griffiths, R. J.
1982-09-01
Coupled channels calculations have been made for the scattering of 7Li from 12C at 63 and 79 MeV and from 24,26Mg at 88 MeV. The calculations describe, simultaneously, the elastic scattering, excitation of 7Li to the 478 keV {1}/{2}- state, excitation of the target to its first 2 + state, and the mutual excitation of both projectile and target to their {1}/{2}- and 2 + states respectively. The potentials have been calculated by a double folding model using the M3Y effective interaction for the real part, and a gaussian effective interaction for the imaginary part. Realistic densities have been used for the ground states of 7Li, 12C and 24, 26Mg and also the transition densities to the excited states using a microscopic plus macroscopic prescription. For the mutual excitation, both one-step processes with l = 0, 2 and 4 and two-step processes were included. The calculations show that the two-step processes are the dominant contribution to the mutual excitation, but at forward angles, the oscillations in the data are only reproduced with the coherent addition of the one-step processes, which are dominated by the l = 4 contribution. Even when coupling to all single and mutual excitations are included the real potential still requires a normalization of about 0.6. The addition of the quadrupole re-orientation matrix element for the ground state does not significantly change this value. These calculations confirm that the coupling to the first excited inelastic levels of target and ejectile is not the source of the anomalous M3Y normalization, and that the dominant mode for mutual excitation is a two-step process. However, direct one-step mutual excitation is important for small angles (θ ≲ 20°).
Interference scattering effects on intermediate resonance absorption at operating temperatures
Resonance integrals may be accurately calculated using the intermediate resonance (IR) approximation. Results are summarized for the case of an absorber with given potential scattering cross sections and interference scattering parameter admixed with a non absorbing moderator of given cross section and located in a narrow resonance moderating medium. From the form of the IR solutions, it is possible to make some general observations about effects of interference scattering on resonance absorption. 2 figures
The charge-symmetric scattering systems, 12C+13N and 12C+13C have been investigated by using the orthogonalized coupled-reaction-channel (OCRC) method with the basis functions of the elastic, inelastic and transfer channels defined by the single-particle states, 1p1/2, 2s1/2, 1d5/2 and 1d3/2 of the valence nucleon in 13N or 13C. The data of the elastic scattering of 13N on 12C measured by Lienard et al. have been explained consistently with the data of the elastic and inelastic scattering of the 12C+13C system. The CRC effects both on the above systems are very strong, although those on the 12C+13N system are fairly weaker than the 12C+13C system. The role of the highly excited single-particle states 1d3/2 is particularly important in the formation of a specific CRC scheme, i.e., the formation of the covalent molecules due to the hybridization caused by the mixing of the different parity single-particle states. The fusion cross sections of the 12C+13C system at energies below the Coulomb barrier are strongly enhanced as a result of the strong CRC effects as compared with those of the 12C+12C system, while in 12C+13N system the enhancement of the sub-barrier fusion has not been observed. The above absorption mechanism for the 12C+13C system explains the lack of the molecular-resonance phenomena observed in the 12C+12C system. We check the effects of the dipole (E1) transition of the valence nucleon in 13N (and also in 13C) due to the core-core Coulomb interaction in the scattering at sub-barrier energies. The effects are not appreciable. (author)
Resonant electromagnetic scattering in anisotropic layered media
The resonant excitation of an electromagnetic guided mode of a slab structure by exterior radiation results in anomalous scattering behavior, including sharp energy-transmission anomalies and field amplification around the frequency of the slab mode. In the case of a periodically layered ambient medium, anisotropy serves to couple the slab mode to radiation. Exact expressions for scattering phenomena are proved by analyzing a pole of the full scattering matrix as it moves off the real frequency axis into the lower half complex plane under a detuning of the wavevector parallel to the slab. The real pole is the frequency of a perfect (infinite Q) guided mode, which becomes lossy as the frequency gains an imaginary part. This work extends results of Shipman and Venakides to evanescent source fields and two-dimensional parallel wavevector and demonstrates by example how the latter allows one to control independently the width and central frequency of a resonance by varying the angle of incidence of the source field. The analysis relies on two nondegeneracy conditions of the complex dispersion relation for slab modes (relating poles of the scattering matrix to wavevector), which were assumed in previous works and are proved in this work for layered media. One of them asserts that the dispersion relation near the wavevector κ and frequency ω of a perfect guided mode is the zero set of a simple eigenvalue ℓ(κ, ω), and the other relates ∂ℓ/∂ω to the total energy of the mode, thereby implying that this derivative is nonzero
Resonant Raman scattering off neutral quantum dots
Resonant inelastic (Raman) light scattering off neutral GaAs quantum dots which contain a mean number, N=42, of electron-hole pairs is computed. We find Raman amplitudes corresponding to strongly collective final states (charge-density excitations) of similar magnitude as the amplitudes related to weakly collective or single-particle excitations. As a function of the incident laser frequency or the magnetic field, they are rapidly varying amplitudes. It is argued that strong Raman peaks should come out in the spin-density channels, not related to valence-band mixing effects in the intermediate states. (author)
Fano resonances in scattering: an alternative perspective
Schwarz, Lukas; Cartarius, Holger; Wunner, Günter; Heiss, Walter Dieter; Main, Jörg
2015-08-01
In a previous paper it has been shown that the interference of the first and second order pole of the Green's function at an exceptional point, as well as the interference of the first order poles in the vicinity of the exceptional point, gives rise to asymmetric scattering cross section profiles. In the present paper we demonstrate that these line profiles are indeed well described by the Beutler-Fano formula, and thus are genuine Fano resonances. Also further away from the exceptional points excellent agreement can be found by introducing energy dependent Fano parameters.
Fano resonances in scattering: an alternative perspective
Schwarz, Lukas; Wunner, Günter; Heiss, Walter Dieter; Main, Jörg
2015-01-01
In a previous paper it has been shown that the interference of the first and second order pole of the Green's function at an exceptional point, as well as the interference of the first order poles in the vicinity of the exceptional point, gives rise to asymmetric scattering cross section profiles. In the present paper we demonstrate that these line profiles are indeed well described by the Beutler-Fano formula, and thus are genuine Fano resonances. Also further away from the exceptional points excellent agreement can be found by introducing energy dependent Fano parameters.
Resonances, scattering theory and rigged Hilbert spaces
The problem of decaying states and resonances is examined within the framework of scattering theory in a rigged Hilbert space formalism. The stationary free, in, and out eigenvectors of formal scattering theory, which have a rigorous setting in rigged Hilbert space, are considered to be analytic functions of the energy eigenvalue. The value of these analytic functions at any point of regularity, real or complex, is an eigenvector with eigenvalue equal to the position of the point. The poles of the eigenvector families give origin to other eigenvectors of the Hamiltonian; the singularities of the out eigenvector family are the same as those of the continued S matrix, so that resonances are seen as eigenvectors of the Hamiltonian with eigenvalue equal to their location in the complex energy plane. Cauchy theorem then provides for expansions in terms of complete sets of eigenvectors with complex eigenvalues of the Hamiltonian. Applying such expansions to the survival amplitude of a decaying state, one finds that resonances give discrete contributions with purely exponential time behavior; the background is of course present, but explicitly separated. The resolvent of the Hamiltonian, restricted to the nuclear space appearing in the rigged Hilbert space, can be continued across the absolutely continuous spectrum; the singularities of the continuation are the same as those of the out eigenvectors. The free, in and out eigenvectors with complex eigenvalues and those corresponding to resonances can be approximated by physical vectors in the Hilbert space, as plane waves can. The need for having some further physical information in addition to the specification of the total Hamiltonian is apparent in the proposed framework. The formalism is applied to the Lee-Friedrichs model. 48 references
The determination of polarization transfer observable for (rvec p, rvec p') reactions in intermediate energies provides a rich source of information on both the effective nucleon-nucleus interaction and the nuclear structure. The primary motivation for this work was to exploit the increased sensitivity predicted for these polarization transfer observable to the spin-dependent terms of the effective interaction used to describe nucleon-nucleus scattering at intermediate energies. To carry out this work the author has designed, built, and calibrated a polarimeter for the focal plane of the high resolution K600 Spectrometer. By using a low-energy beamline polarimeter and this Focal Plane Polarimeter, he has measured the normal-component spin observables DNN', P, and Ay at 200 MeV for the 1+, T = 0 (12.71 MeV) and T = 1 (15.11 MeV) states in 12C and for the 4-, T = 0 (17.79 and 19.80 MeV) and T = 1 (18.98 MeV) states in 16O. Measurements were made at five angles for the 12C transitions, at momentum transfers between 80 and 250 MeV/c, and at three angles for 16O, at momentum transfers of 225 to 400 MeV/c. The transitions chosen for this work have fairly well-determined nuclear structure and unnatural parity which maximizes the predicted sensitivity to the spin-dependent terms of the effective interaction. The results from this work will be used to address questions concerning the need for a relativistic interaction and how to incorporate corrections to the nuclear interaction due to the nuclear medium
Resonances and off-specular scattering in neutron waveguides
Off-specular neutron scattering from layered resonant systems has been studied. As an example, tri-layer neutron waveguides have been investigated experimentally by neutron reflectometry. In such systems, the neutron wave function is strongly localized in the guiding layer. The resonant states in the total reflection region lead to enhanced off-specular scattering from the interface roughness. The relation between the resonant states and off-specular scattering is discussed. (authors)
Resonances and off-specular scattering in neutron waveguides
Kozhevnikov, S.V. [Franck Lab. of Neutron Physics, JINR, Moscow (Russian Federation); Kozhevnikov, S.V.; Ott, F. [CEA Saclay, IRAMIS, CNRS, Lab. Leon Brillouin, 91 - Gif-sur-Yvette (France); Paul, A. [Institut fur Festkorperforschung, Forschungszentrum Julich (Germany); Rosta, L. [Research Institute for Solid State Physics and Optics, Budapest (Hungary)
2009-02-15
Off-specular neutron scattering from layered resonant systems has been studied. As an example, tri-layer neutron waveguides have been investigated experimentally by neutron reflectometry. In such systems, the neutron wave function is strongly localized in the guiding layer. The resonant states in the total reflection region lead to enhanced off-specular scattering from the interface roughness. The relation between the resonant states and off-specular scattering is discussed. (authors)
The Use of the Scattering Phase Shift in Resonance Physics
Nowakowski, M
2004-01-01
The scattering phase shift encodes a good amount of physical information which can be used to study resonances from scattering data. Among others, it can be used to calculate the continuum density of states and the collision time in a resonant process. Whereas the first information can be employed to examine the evolution of unstable states directly from scattering data, the second one serves as a tool to detect resonances and their properties. We demonstrate both methods concentrating in the latter case on 'exotic' resonances in pi-pi and pi-K scattering.
Observation of resonant lattice modes by inelastic neutron scattering
Bjerrum Møller, Hans; Mackintosh, A.R.
1965-01-01
Observation by inelastic neutron scattering of resonant lattice modes due to small concentration of W atoms in Cr host crystal; frequencies and lifetimes of phonons with frequencies near that of resonant mode are considerably affected by presence of defects.......Observation by inelastic neutron scattering of resonant lattice modes due to small concentration of W atoms in Cr host crystal; frequencies and lifetimes of phonons with frequencies near that of resonant mode are considerably affected by presence of defects....
X-ray resonant magnetic scattering ellipsometer
It is very difficult to characterize the polarization of a synchrotron radiation source in the soft and/or intermediate x-ray energy region particularly from 1 to 2 keV. Conventional multilayer mirror or single-crystal polarimeters do not work over this energy region because their throughput (the reflectivities combined with the phase shift) becomes insignificant. In this paper, we present a new ellipsometer scheme that is able to fully characterize the polarization of synchrotron radiation sources in this energy region. It is based on the dichroic x-ray resonant ferromagnetic scattering that yields information on both the polarization of the x-ray and the material (element specific) dielectric-constant tensor [C.-C. Kao et al., Phys. Rev. B 50, 9599 (1994)] due to the interband ferromagnetic Kerr effect [B.R. Cooper, Phys. Rev. A 139, 1504 (1965)]. copyright 1996 American Institute of Physics
Scattering and Resonances in QCD_2
Frishman, Yitzhak; Frishman, Yitzhak; Karliner, Marek
2002-01-01
Extending previous works on the spectrum of QCD_2, we now investigate the 2D analogue of meson-baryon scattering. We use semi-classical methods, perturbing around classical soliton solutions. We start with the abelian case, corresponding to QED_2 and find that in this case the effective potential is reflectionless. We obtain an explicit expression for the forward phase shift. In the non-abelian case of QCD_2, the method yields a potential which depends on the momentum of the incoming particle. In this case there is both transmission and reflection. In both cases no resonances appear. As a byproduct, we derive the general conditions for a 2D quantum field theoretical action to yield a reflectionless effective potential when one expands in small fluctuations about the classical solution.
Physics of Cyclotron Resonance Scattering Features
Sschoenherr, Gabriele; Schwarm, Fritz-Walter; Falkner, Sebastian; Dauser, Thomas; Pottschmidt, Katja; Kretschmar, Peter; Klochkov, Dmitry; Ferrigno, Carlo; Britton Hemphill, Paul; Wilms, Joern
2016-04-01
Cyclotron resonant scattering features (short: cyclotron lines) are sensitive tracers of the physics of the accretion columns and mounds of X-ray pulsars. They form by interaction of X-ray photons with magnetically quantized electrons in the accreted plasma close to the neutron star. Such lines have been observed as absorption-like features for about 20 X-ray pulsars. Their energies provide a direct measure of the magnetic field strength in the line-forming region. By detailed modelling of the lines and of their parameter dependencies we can further decipher the physical conditions in the accretion column. For instance the fact that the complex scattering cross sections have a strong angle-dependence relates the phase-resolved cyclotron line shapes to parameters that constrain the systems’ still poorly understood geometry. Modelling the physics of cyclotron lines to a degree that allows for detailed and solid comparison to data therefore provides a unique access also to a better understanding of the overall picture of magnetically accreting neutron star systems.
Fano resonance scattering in waveguide with an impedance boundary condition
Xiong, Lei; Aurégan, Yves
2015-01-01
Sound propagation in a waveguide lined with one section of locally reactive material is studied by resonance scattering approach. The objective is to understand the effects of mode coupling in the lined section on the transmission. It is shown that a transmission zero is present in the vicinity of a resonance peak when a numerically real resonance frequency of the open lined section (opened to infinities through the rigid parts of the waveguide) is crossed. The transmission zero and immediate resonance peak form a Fano resonance, it has been explained as an interaction between a resonance and the non-resonant background. The real resonance frequency and its corresponding trapped mode are formed by the interferences (couplings) between two neighbor modes with complex resonance frequencies. It is also linked to the avoided crossing of eigenvalues and the exceptional point. The scattering matrix is expressed in terms of a matrix $\\mathsf{H_{eff}}$ which describes approximately the complex resonances in the open ...
Mie scattering as a cascade of Fano resonances.
Rybin, Mikhail V; Samusev, Kirill B; Sinev, Ivan S; Semouchkin, George; Semouchkina, Elena; Kivshar, Yuri S; Limonov, Mikhail F
2013-12-01
We reveal that the resonant Mie scattering by high-index dielectric nanoparticles can be presented through cascades of Fano resonances. We employ the exact solution of Maxwell's equations and demonstrate that the Lorenz-Mie coefficients of the Mie problem can be expressed generically as infinite series of Fano functions as they describe interference between the background radiation originated from an incident wave and narrow-spectrum Mie scattering modes that lead to Fano resonances. PMID:24514559
Scatter-based magnetic resonance elastography
Elasticity is a sensitive measure of the microstructural constitution of soft biological tissues and increasingly used in diagnostic imaging. Magnetic resonance elastography (MRE) uniquely allows in vivo measurement of the shear elasticity of brain tissue. However, the spatial resolution of MRE is inherently limited as the transformation of shear wave patterns into elasticity maps requires the solution of inverse problems. Therefore, an MRE method is introduced that avoids inversion and instead exploits shear wave scattering at elastic interfaces between anatomical regions of different shear compliance. This compliance-weighted imaging (CWI) method can be used to evaluate the mechanical consistency of cerebral lesions or to measure relative stiffness differences between anatomical subregions of the brain. It is demonstrated that CWI-MRE is sensitive enough to reveal significant elasticity variations within inner brain parenchyma: the caudate nucleus (head) was stiffer than the lentiform nucleus and the thalamus by factors of 1.3 ± 0.1 and 1.7 ± 0.2, respectively (P < 0.001). CWI-MRE provides a unique method for characterizing brain tissue by identifying local stiffness variations.
Impact of polydispersity on multipolar resonant scattering in emulsions.
Mascaro, Benoit; Brunet, Thomas; Poncelet, Olivier; Aristégui, Christophe; Raffy, Simon; Mondain-Monval, Olivier; Leng, Jacques
2013-04-01
The influence of size polydispersity on the resonant acoustic properties of dilute emulsions, made of fluorinated-oil droplets, is quantitatively investigated. Ultrasound attenuation and dispersion measurements on various samples with controlled size polydispersities, ranging from 1% to 13%, are found to be in excellent agreement with predictions based on the independent scattering approximation. By relating the particle-size distribution of the synthesized emulsions to the quality factor of the predicted multipolar resonances, the number of observable acoustic resonances is shown to be imposed by the sample polydispersity. These results are briefly discussed into the context of metamaterials for which scattering resonances are central to their effective properties. PMID:23556570
Low Frequency Scattering Resonance Wave in Strong Heterogeneity
Liu, Yinbin
2015-01-01
Multiple scattering of wave in strong heterogeneity can cause resonance-like wave phenomenon where signal exhibits low frequency, high intensity, and slowly propagating velocity. For example, long period event in volcanic seismology and surface plasmon wave and quantum Hall effect in wave-particle interactions. Collective behaviour in a many-body system is usually thought to be the source for generating the anomaly. However, the detail physical mechanism is not fully understood. Here I show by wave field modeling for microscopic bubble cloud model and 1D heterogeneity that the anomaly is related to low frequency scattering resonance happened in transient regime. This low frequency resonance is a kind of wave coherent scattering enhancement phenomenon in strongly-scattered small-scale heterogeneity. Its resonance frequency is inversely proportional to heterogeneous scale and contrast and will further shift toward lower frequency with random heterogeneous scale and velocity fluctuations. Low frequency scatterin...
Improved Fokker-Planck Equation for Resonance Line Scattering
Rybicki, G B
2006-01-01
A new Fokker-Planck equation is developed for treating resonance line scattering, especially relevant to the treatment of Lyman alpha in the early universe. It is a "corrected" form of the equation of Rybicki & Dell'Antonio that now obeys detailed balance, so that the approach to thermal equilibrium is properly described. The new equation takes into account the energy changes due to scattering off moving particles, the recoil term of Basko, and stimulated scattering. One result is a surprising unification of the equation for resonance line scattering and the Kompaneets equation. An improved energy exchange formula due to resonance line scattering is derived. This formula is compared to previous formulas of Madau, Meikson, & Rees (1997) and Chen & Miralda-Escud\\'e (2004).
Strong WW scattering chiral lagrangians, unitarity and resonances
Pelaez, J.R.
1996-08-01
Chiral lagrangians provide a model independent description of the strongly interacting symmetry breaking sector. In this work, first we review the LHC sensitivity to the chiral parameters (in the hardest case of non-resonant low-energy WW scattering). Later we show how to reproduce or predict the resonance spectrum by means of dispersion theory and the inverse amplitude method. We present a parameter space scan that covers many different strong WW scattering scenarios.
Photoproduction of pions in 12C nuclei
A preliminary analysis was carried out of relativistic effects in coherent and incoherent pion production for the reaction 12C(γ, π0)12C by considering all the diagrams that contribute to the scattering amplitude. For the coherent pion the contribution to the scattering cross section mainly comes from the direct and exchange diagrams of γN → Δ → Nπ0, where N is a nucleon. The results were compared with the nonrelativistic calculations done in 12C nuclei assuming the nuclear effects and the final state interactions to be the same
Correlation signals in resonance fluorescence : interpretation via photon scattering amplitudes
Dalibard, J.; Reynaud, S.
1983-01-01
Resonance fluorescence is treated as a collision process where incident laser photons are scattered by an atom. Correlation signals are extracted from an expansion to the second order of the post collision field state. Photon antibunching effect appears as a quantum interference between all the possible scattering amplitudes. When Rayleigh photons are rejected, some amplitudes vanish, leading to a bunching behaviour.
Resonance scattering characteristics of double-layer spherical particles
Xuejin Dong; Mingxu Su; Xiaoshu Cai
2012-01-01
Based on the principle of ultrasonic resonance scattering,sound-scattering characteristics of double-layer spherical particles in water were numerically studied in this paper.By solving the equations of the scattering matrix,the scattering coefficient determined by the boundary conditions can be obtained,thus the expression for the sound-scattering function of a single double-layer spherical particle can be derived.To describe the resonance scattering characteristics of a single particle,the reduced scattering cross section and reduced extinction cross section curves were found through numerical calculation.Similarly,the numerically calculated sound attenuation coefficient curves were used to depict the resonance scattering characteristics of monodisperse and polydisperse particles.The results of numerical calculation showed that,for monodisperse particles,the strength of the resonance was mainly related to the particle size and the total number of particles; while for polydisperse particles,it was primarily affected by the particle size,the coverage of the particle size distribution and the particle concentration.
Nuclear resonant scattering of capture gamma rays on Sb
Monochromatic photons obtained from thermal neutron capture in titanium were used for exciting nuclear levels in antimony. Angular distribution of the elastic scattered radiation was carried-out for the determination of the spins of the resonance levels. Total and ground state radiation widths of resonance levels were measured using self absorption and temperature variation measurements
Resonant Raman scattering of x rays: Evidence for K-M scattering
Resonant Raman x-ray scattering on molybdenum was studied using a Mo-anode x-ray tube and a LiF crystal monochromator. Beside the usual resonant Raman peak corresponding to the fluorescent Kα lines, another peak with a smaller energy loss was found. It is attributed to resonant Raman scattering with a final-state M-shell vacancy corresponding to the fluorescent Kβ lines. Both contributions are shown to be independent of the scattering angle. Absolute cross sections have been determined and compared with theoretical predictions
Resonant Raman scattering of x rays: evidence for K--M scattering
Resonant Raman x-ray scattering on molybdenum was studied using a Mo-anode x-ray tube and a LiF crystal monochromator. Beside the usual resonant Raman peak corresponding to the fluorescent Kα lines another peak with a smaller energy loss was found. It is attributed to resonant Raman scattering with a final state M-shell vacancy corresponding to the fluorescent Kβ lines. Both contributions are shown to be independent of the scattering angle. Absolute cross sections were determined and compared with theoretical predictions. 9 references
Guddala, Sriram; Ramakrishna, S Anantha
2016-01-01
A tri-layer metamaterial perfect absorber of light, consisting of (Al/ZnS/Al) films with the top aluminium layer patterned as an array of circular disk nanoantennas, is investigated for resonantly enhancing Raman scattering from C-60 fullerene molecules deposited on the metamaterial. The metamaterial is designed to have resonant bands due to plasmonic and electromagnetic resonances at the Raman pump frequency (725 nm) as well as Stokes emission bands. The Raman scattering from C60 on the metamaterial with resonantly matched bands is measured to be enhanced by an order of magnitude more than from C60 on metamaterials with off-resonant absorption bands peaked at 1090 nm. The Raman pump is significantly enhanced due to the resonance with a propagating surface plasmon band, while the highly impedance matched electromagnetic resonance is expected to couple out the Raman emission efficiently. The nature and hybridization of the plasmonic and electromagnetic resonances to form compound resonances are investigated by...
Tailoring dielectric resonator geometries for directional scattering and Huygens' metasurfaces
Campione, Salvatore; Basilio, Lorena I.; Warne, Larry K.; Sinclair, Michael B.
2015-02-01
In this paper we describe a methodology for tailoring the design of metamaterial dielectric resonators, which represent a promising path toward low-loss metamaterials at optical frequencies. We first describe a procedure to decompose the far field scattered by subwavelength resonators in terms of multipolar field components, providing explicit expressions for the multipolar far fields. We apply this formulation to confirm that an isolated high-permittivity cube resonator possesses frequency separated electric and magnetic dipole resonances, as well as a magnetic quadrupole resonance in close proximity to the electric dipole resonance. We then introduce multiple dielectric gaps to the resonator geometry in a manner suggested by perturbation theory, and demonstrate the ability to overlap the electric and magnetic dipole resonances, thereby enabling directional scattering by satisfying the first Kerker condition. We further demonstrate the ability to push the quadrupole resonance away from the degenerate dipole resonances to achieve local behavior. These properties are confirmed through the multipolar expansion and show that the use of geometries suggested by perturbation theory is a viable route to achieve purely dipole resonances for metamaterial applications such as wave-front manipulation with Huygens' metasurfaces. Our results are fully scalable across any frequency bands where high-permittivity dielectric materials are available, including microwave, THz, and infrared frequencies.
Optical Torque from Enhanced Scattering by Multipolar Plasmonic Resonance
Lee, Yoonkyung E; Jin, Dafei; Fang, Nicholas
2014-01-01
We present a theoretical study of the optical angular momentum transfer from a circularly polarized plane wave to thin metal nanoparticles of different rotational symmetries. While absorption has been regarded as the predominant mechanism of torque generation on the nanoscale, we demonstrate numerically how the contribution from scattering can be enhanced by using multipolar plasmon resonance. The multipolar modes in non-circular particles can convert the angular momentum carried by the scattered field, thereby producing scattering-dominant optical torque, while a circularly symmetric particle cannot. Our results show that the optical torque induced by resonant scattering can contribute to 80% of the total optical torque in gold particles. This scattering-dominant torque generation is extremely mode-specific, and deserves to be distinguished from the absorption-dominant mechanism. Our findings might have applications in optical manipulation on the nanoscale as well as new designs in plasmonics and metamateria...
Resonant Cyclotron Scattering and Comptonization in Neutron Star Magnetospheres
Lyutikov, M; Lyutikov, Maxim; Gavriil, Fotis P.
2006-01-01
Resonant cyclotron scattering of the surface radiation in the magnetospheres of neutron stars may considerably modify the emergent spectra and impede efforts to constraint neutron star properties. Resonant cyclotron scattering by a non-relativistic warm plasma in an inhomogeneous magnetic field has a number of unusual characteristics: (i) in the limit of high resonant optical depth, the cyclotron resonant layer is half opaque, in sharp contrast to the case of non-resonant scattering. (ii) The transmitted flux is on average Compton up-scattered by ~ $1+ 2 beta_T$, where $\\beta_T$ is the typical thermal velocity in units of the velocity of light; the reflected flux has on average the initial frequency. (iii) For both the transmitted and reflected fluxes the dispersion of intensity decreases with increasing optical depth. (iv) The emergent spectrum is appreciably non-Plankian while narrow spectral features produced at the surface may be erased. (v) Optical photons are less affected by resonant Comptonization tha...
Resonance scattering of canonical elastic shells in absorbing fluid medium
ZHUO Linkai; FAN Jun; TANG Weilin
2008-01-01
Resonance scattering of elastic spherical shell and cylindrical shell while the sur-rounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable resul twould be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surround-ing fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little in fluence on the low-frequency resonance scattering induced by the filler inside the shell.
Resonance magnetic x-ray scattering study of erbium
Sanyal, M.K.; Gibbs, D.; Bohr, J.;
1994-01-01
of this magnetic scattering and analyzed it using a simple model based on electric dipole and quadrupole transitions among atomic orbitals. The line shapes can be fitted to a magnetic structure combining both c-axis-modulated and basal-plane components. Below 18 K, we have observed unusual behavior......The magnetic phases of erbium have been studied by resonance x-ray-scattering techniques. When the incident x-ray energy is tuned near the L(III) absorption edge, large resonant enhancements of the magnetic scattering are observed above 18 K. We have measured the energy and polarization dependence...... of the magnetic scattering as a function of energy, whose origin is not understood....
Resonance propagation in heavy-ion scattering
Bijoy Kundu; B K Jain
2001-06-01
The formalism developed earlier by us for the propagation of a resonance in the nuclear medium in proton–nucleus collisions has been modiﬁed to the case of vector boson production in heavy-ion collisions. The formalism includes coherently the contribution to the observed di-lepton production from the decay of a vector boson inside as well as outside the nuclear medium. The medium modiﬁcation of the boson is incorporated through an energy dependent optical potential. The calculated invariant mass distributions are presented for the -meson production using optical potentials estimated within the VDM and the resonance model. The shift in the invariant mass distribution is found to be small. To achieve the mass shift (of about 200 MeV towards lower mass) as indicated in the high energy heavy-ion collision experiments, an unusually strong optical potential of about -120 MeV is required. We also observe that, for not so heavy nuclear systems and/or for fast moving resonances, the shape, magnitude and peak position of the invariant mass distribution is substantially different if the contributions from the resonance decay inside and outside are summedup at the amplitude level (coherently) or at the cross section level (incoherently).
Self-Consistent Scattering Calculation of Resonant Tunneling Diode Characteristics
Sun, J P; Haddad, G. I.
1998-01-01
We perform a self-consistent calculation of resonant tunneling diode (RTD) I-V characteristics including optical phonon scattering. The self-consistency is obtained by solving the Schrödinger equation and Poisson’s equation iteratively with the Thomas-Fermi approximation used for the device contact regions. For evaluation of phonon-assisted current density, the optical phonon scattering in the quantum well is modeled using the optical model potential. Electron transverse momentum is also inco...
New Physics / Resonances in Vector Boson Scattering at the LHC
Reuter, J; Ohl, T; Sekulla, M
2016-01-01
Vector boson scattering is (together with the production of multiple electroweak gauge bosons) the key process in the current run 2 of LHC to probe the microscopic nature of electroweak symmetry breaking. Deviations from the Standard Model are generically parameterized by higher-dimensional operators, however, there is a subtle issue of perturbative unitarity for such approaches for the process above. We discuss a parameter-free unitarization prescription to get physically meaningful predictions. In the second part, we construct simplified models for generic new resonances that can appear in vector boson scattering, with a special focus on the technicalities of tensor resonances.
Fano Resonance Enhanced Nonreciprocal Absorption and Scattering of Light
Ben Hopkins
2015-06-01
Full Text Available We reveal that asymmetric plasmonic nanostructures can exhibit significantly different absorption and scattering properties for light that propagates in opposite directions, despite the conservation of total extinction. We analytically demonstrate that this is a consequence of nonorthogonality of eigenmodes of the system. This results in the necessity for modal interference with potential enhancement via Fano resonances. Based on our theory, we propose a stacked nanocross design whose optical response exhibits an abrupt change between absorption and scattering cross-sections for plane waves propagating in opposite directions. This work thereby proposes the use of Fano resonances to employ nanostructures for measuring and distinguishing optical signals coming from opposite directions.
Resonant Raman Scattering from Silicon Nanoparticles Enhanced by Magnetic Response
Dmitriev, Pavel A; Milichko, Valentin A; Makarov, Sergey V; Mukhin, Ivan S; Samusev, Anton K; Krasnok, Alexander E; Belov, Pavel A; Kivshar, Yuri S
2016-01-01
Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions.
Resonant Raman scattering from silicon nanoparticles enhanced by magnetic response.
Dmitriev, Pavel A; Baranov, Denis G; Milichko, Valentin A; Makarov, Sergey V; Mukhin, Ivan S; Samusev, Anton K; Krasnok, Alexander E; Belov, Pavel A; Kivshar, Yuri S
2016-05-01
Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have a much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of the Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions. PMID:27113352
Resonances in low-energy positron-alkali scattering
Horbatsch, M.; Ward, S. J.; Mceachran, R. P.; Stauffer, A. D.
1990-01-01
Close-coupling calculations were performed with up to five target states at energies in the excitation threshold region for positron scattering from Li, Na and K. Resonances were discovered in the L = 0, 1 and 2 channels in the vicinity of the atomic excitation thresholds. The widths of these resonances vary between 0.2 and 130 MeV. Evidence was found for the existence of positron-alkali bound states in all cases.
Resonance eigenfunctions in chaotic scattering systems
Martin Sieber
2009-09-01
We study the semiclassical structure of resonance eigenstates of open chaotic systems. We obtain semiclassical estimates for the weight of these states on different regions in phase space. These results imply that the long-lived right (left) eigenstates of the non-unitary propagator are concentrated in the semiclassical limit ħ → 0 on the backward (forward) trapped set of the classical dynamics. On this support the eigenstates display a self-similar behaviour which depends on the limiting decay rate.
E791 Collaboration; Leksanov, A.; Alster, J.; Asryan, G.; Averichev, Y.; Barton, D; Baturin, V.; Bukhtoyarova, N.; Carroll, A.; Heppelmann, S.; Kawabata, T.; Makdisi, Y.; Malki, A.; Minina, E.; Navon, I.
2000-01-01
We present a new measurement of the energy dependence of nuclear transparency from AGS experiment E850, performed using the EVA solenoidal spectrometer, upgraded since 1995. Using a secondary beam from the AGS accelerator, we simultaneously measured $pp$ elastic scattering from hydrogen and $(p,2p)$ quasi-elastic scattering in carbon at incoming momenta of 5.9, 8.0, 9.0, 11.7 and 14.4 GeV/c. This incident momentum range corresponds to a $Q^{2}$ region between 4.8 and 12.7 (GeV/c)$^{2}$. The d...
Resonantly enhanced Bragg-scattering spectroscopy of an atomic transition
Yang, Xudong; Qiao, Cuifang; Li, Chuanliang; Chen, Fenghua
2016-07-01
A novel resonantly enhanced Bragg-scattering (REBS) spectroscopy from a population difference grating (PDG) is reported. The PDG is formed by a standing-wave (SW) pump field, which periodically modulates the space population distributions of two levels in the 87Rb D1 line. Then, a probe beam, having identical frequency and orthogonal polarization with the SW pump field, is Bragg-scattered by the PDG. The research achievement shows that the Bragg-scattered light is strongest at an atomic transition, and forms an REBS spectrum with a high signal-to-noise ratio and sub-natural linewidth. The observed REBS can be applied in precise frequency measurements.
Resonant Raman scattering from silicon nanoparticles enhanced by magnetic response
Dmitriev, Pavel A.; Baranov, Denis G.; Milichko, Valentin A.; Makarov, Sergey V.; Mukhin, Ivan S.; Samusev, Anton K.; Krasnok, Alexander E.; Belov, Pavel A.; Kivshar, Yuri S.
2016-05-01
Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have a much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of the Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions.Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have a much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of the Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07965a
D Pi scattering and D meson resonances from lattice QCD
Mohler, Daniel; Woloshyn, R M
2012-01-01
The masses and widths of the broad scalar D_0^*(2400) and the axial D_1(2430) charmed-light resonances are extracted by simulating the corresponding D Pi and D* Pi scattering on the lattice. The resonance parameters are obtained using a Breit-Wigner fit of the elastic phase shifts. The resulting D_0^*(2400) mass is 351+/-21 MeV above the spin-average 1/4(m_D+3m_{D*}), in agreement with the experimental value of 347+/-29 MeV above. The resulting D_0^* to D Pi coupling g^{lat}=2.55+/-0.21 GeV is close to the experimental value g^{exp}<=1.92+/-0.14 GeV, where g parametrizes the width $\\Gamma\\equiv g^2p^*/s$. The resonance parameters for the broad D_1(2430) are also found close to the experimental values; these are obtained by appealing to the heavy quark limit, where the neighboring resonance D_1(2420) is narrow. The calculated I=1/2 scattering lengths are a_0=0.81+/-0.14 fm for D Pi and a_0=0.81+/-0.17 fm for D* Pi scattering. The simulation of the scattering in these channels incorporates quark-antiquark as...
Resonance structure in elastic scattering of electrons from atomic hydrogen
Warner, C.D.; King, G.C.; Hammond, P.; Slevin, J.
1986-10-28
High-energy-resolution spectra of electrons scattered elastically from atomic hydrogen have been obtained for incident electron energies of 9.2-10.4 eV and at angles of 33/sup 0/, 54/sup 0/, 70/sup 0/ and 90/sup 0/. The energy spread of the incident electron beam is estimated to be typically 25 meV FWHM. In addition to the /sup 1/S and /sup 3/P resonances which have been reported in earlier studies, a /sup 1/D resonance can be clearly seen and there is some evidence of a resonance state at a higher energy, probably corresponding to a /sup 1/S resonance state. The energies and resonance widths of all these features have been determined.
Resonance structure in elastic scattering of electrons from atomic hydrogen
High-energy-resolution spectra of electrons scattered elastically from atomic hydrogen have been obtained for incident electron energies of 9.2-10.4 eV and at angles of 330, 540, 700 and 900. The energy spread of the incident electron beam is estimated to be typically 25 meV FWHM. In addition to the 1S and 3P resonances which have been reported in earlier studies, a 1D resonance can be clearly seen and there is some evidence of a resonance state at a higher energy, probably corresponding to a 1S resonance state. The energies and resonance widths of all these features have been determined. (author)
Leksanov, A.; Alster, J.; Asryan, G.; Averichev, Y.; Barton, D.; Baturin, V.; Bukhtojarova, N.; Carroll, A.; Schetkovsky, A.; Heppelmann, S.; Kawabata, T.; Malki, A.; Makdisi, Y.; Minina, E.; Navon, I.; Nicholson, H.; Ogawa, A.; Panebratsev, Y.; Piasetzky, E.; Shimanskiy, S.; Tang, A.; Watson, J. W.; Yoshida, H.; Zhalov, D.
2000-12-01
We present a new measurement of the energy dependence of nuclear transparency from AGS experiment E850, performed using the EVA solenoidal spectrometer, upgraded since 1995. Using a secondary beam from the AGS accelerator, we simultaneously measured pp elastic scattering from hydrogen and (p,2p) quasi-elastic scattering in carbon at incoming momenta of 5.9, 8.0, 9.0, 11.7 and 14.4 GeV/c. This incident momentum range corresponds to a Q2 region between 4.8 and 12.7 (GeV/c)2. The detector allowed us to do a complete kinematic analysis for the center-of-mass polar angles in the range 85°-90°. We report on the measured variation of the nuclear transparency with energy and compare the new results with previous measurements.
Simultaneous χ2 analyses are performed for elastic scattering and fusion cross section data for the 12C+208Pb system at near-Coulomb-barrier energies by using the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts. Use is made of the double folding potential as a bare potential. It is found that the experimental elastic scattering and fusion data are well reproduced without introducing any normalization factor for the double folding potential and also that both DR and fusion parts of the polarization potential determined from the χ2 analyses satisfy separately the dispersion relation. Furthermore, it is shown that the imaginary parts of both DR and fusion potentials at the strong absorption radius change very rapidly, which results in a typical threshold anomaly in the total imaginary potential as observed with tightly bound projectiles such as α-particle and 16O
Reduced transport velocity of multiply scattered light due to resonant scattering
Störzer, Martin; Aegerter, Christof M; Maret, Georg
2006-01-01
The transport properties of photons traveling through random media are of great fundamental and applied importance. For instance the dwell time due to resonant Mie scattering can lead to a significant reduction in transport velocity. Here, we have measured directly the energy-transport velocity of photons in strongly scattering media using a combination of time resolved transmission, measuring the diffusion coefficient, and angular resolved backscattering, yielding the transport mean free pat...
Yao, Xiaojun; Müller, Berndt
2016-01-01
We study the dynamical screening effect in the QED plasma on the $\\alpha$-$\\alpha$ scattering at the $^8$Be resonance. Dynamical screening leads to an imaginary part of the potential which results in a thermal width for the resonance and dominates over the previously considered static screening effect. As a result, both the resonance energy and width increase with the plasma temperature. Furthermore, dynamical screening can have a huge impact on the $\\alpha$-$\\alpha$ thermal nuclear scattering rate. For example, when the temperature is around $10$ keV, the rate is suppressed by a factor of about $900$. We expect similar thermal suppressions of nuclear reaction rates to occur in nuclear reactions dominated by an above threshold resonance with a thermal energy. Dynamical screening effects on nuclear reactions can be relevant to cosmology and astrophysics.
Birkedal, Dan; Shah, Jagdeep; Shchegrov, Andrei V.;
2000-01-01
Resonant Rayleigh scattering from quantum well excitons is investigated using ultrafast spectral interferometry. We isolate the coherent Rayleigh scattering from incoherent luminescence in a single speckle. Averaging the resonant Rayleigh intensity over several speckles allows us to identify...
Resonant proton scattering of $^{22}$Mg and $^{21}$Na
Di julio, D D; Jansson, K; Rudolph, D; Fynbo, H O U; Nilsson, T; Perea martinez, A
In our letter-of-intent, INTC-I-051, we discussed the physics case for scattering and transfer reactions involving light nuclei in the break-out region of the rp-process. The Committee found the physics case compelling and supported the letter-of-intent under the premise that beams of proper quality were developed and that an adequate detector set-up was presented. As these two requirements have been met recently we now propose to study resonant proton scattering of $^{22}$Mg to identify the states at 1.733 MeV and 2.575 MeV in $^{23}$Al that have been reported from the $^{24}$Mg($^{7}$Li,$^{8}$He)$\\,^{23}\\!$Al reaction but that remained unobserved in the only resonant proton scattering experiment performed with $^{22}$Mg so far. In particular we should be able to investigate the character of the proton emission of the 2.575 MeV state which may also have a significant inelastic branch. We also propose to perform resonant proton scattering on $^{21}$Na above $\\alpha$-particle threshold with $^{18}$Ne to study ...
Pion-nucleus scattering at around the DELTA (1232) resonance
Ahmed, H S; Rahman, M A; Rahman, S N
2003-01-01
The pion-nucleus scattering around 200 MeV and just above 1200 MeV is dominated by strong, broad DELTA (3,3) and weak resonances in the pi sup+-N interaction. The interaction to a first approximation can be described as diffraction process. Since it is well known that the strength of the pi sup + N and pi sup - N interactions are quite different from each other at the resonances, the analyses of differential cross section for pi sup + N and pi sup - N elastic scattering data in the region of low-lying pion-nucleus resonances will be a good test of different strengths. In the present work we analyze pions scattering from nuclei sup 9 Be, sup 2 sup 8 Si, sup 5 sup 8 Ni, sup 8 sup 9 Y and sup 2 sup 0 sup 8 Pb at incident pion energies between 50 and 291 MeV within the framework of the three parameter version of the Strong Absorption Model of Frahn and Venter. All the oscillations in the elastic scattering experimental data and for the experimental angular distribution leading to 2 sup + and 3 sup - collective st...
Theory of coherent phenomena and fundamentals in nuclear resonant scattering
We discuss the general theory of coherent phenomena in nuclear resonant interaction of γ-quanta with crystals. The coherence is realized in collective excitation of the ensemble of nuclei (nuclear exciton) with the conservation of phase memory and in the transformation of a γ-quantum into a quasi-particle of Bloch type in a crystal. The collective character of excitations causes a change in the resonant nuclear parameters and in the lifetime of the excited state. This manifests itself in a speed-up of the decay in the forward direction in a thin crystal and, on the contrary, a strong reduction of elastic scattering in a thick crystal. The reconstruction of the wavefunction of an individual γ-quantum in scattering under Laue or Bragg conditions leads to the suppression effect of inelastic incoherent channels. This effect is discussed in detail. The analysis is based on a derived general system of equations describing the resonant diffraction of γ-quanta in a crystal with an arbitrary relation between the coherent and incoherent channels. This system is used to deduce the equations describing the time-dependent nuclear resonant scattering of synchrotron radiation. We discuss the most instructive experiments with revealing coherent phenomena
Resonant magnetic scattering of polarized soft x rays
Sacchi, M. [Centre Universitaire Paris-Sud, Orsay (France); Hague, C.F. [Universite Pierre et Marie Curie, Paris (France); Gullikson, E.M.; Underwood, J. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)
1997-04-01
Magnetic effects on X-ray scattering (Bragg diffraction, specular reflectivity or diffuse scattering) are a well known phenomenon, and they also represent a powerful tool for investigating magnetic materials since it was shown that they are strongly enhanced when the photon energy is tuned across an absorption edge (resonant process). The resonant enhancement of the magnetic scattering has mainly been investigated at high photon energies, in order to match the Bragg law for the typical lattice spacings of crystals. In the soft X-ray range, even larger effects are expected, working for instance at the 2p edges of transition metals of the first row or at the 3d edges of rare earths (300-1500 eV), but the corresponding long wavelengths prevent the use of single crystals. Two approaches have been recently adopted in this energy range: (i) the study of the Bragg diffraction from artificial structures of appropriate 2d spacing; (ii) the analysis of the specular reflectivity, which contains analogous information but has no constraints related to the lattice spacing. Both approaches have their own specific advantages: for instance, working under Bragg conditions provides information about the (magnetic) periodicity in ordered structures, while resonant reflectivity can easily be related to electronic properties and absorption spectra. An important aspect common to all the resonant X-ray scattering techniques is the element selectivity inherent to the fact of working at a specific absorption edge: under these conditions, X-ray scattering becomes in fact a spectroscopy. Results are presented for films of iron and cobalt.
Resonance electronic Raman scattering in rare earth crystals
Williams, G.M.
1988-11-10
The intensities of Raman scattering transitions between electronic energy levels of trivalent rare earth ions doped into transparent crystals were measured and compared to theory. A particle emphasis was placed on the examination of the effect of intermediate state resonances on the Raman scattering intensities. Two specific systems were studied: Ce/sup 3 +/(4f/sup 1/) in single crystals of LuPO/sub 4/ and Er/sup 3 +/(4f/sup 11/) in single crystals of ErPO/sub 4/. 134 refs., 92 figs., 33 tabs.
Resonance electronic Raman scattering in rare earth crystals
The intensities of Raman scattering transitions between electronic energy levels of trivalent rare earth ions doped into transparent crystals were measured and compared to theory. A particle emphasis was placed on the examination of the effect of intermediate state resonances on the Raman scattering intensities. Two specific systems were studied: Ce3+(4f1) in single crystals of LuPO4 and Er3+(4f11) in single crystals of ErPO4. 134 refs., 92 figs., 33 tabs
Resonances and adiabatic invariance in classical and quantum scattering theory
Jain, S R
2004-01-01
We discover that the energy-integral of time-delay is an adiabatic invariant in quantum scattering theory and corresponds classically to the phase space volume. The integral thus found provides a quantization condition for resonances, explaining a series of results recently found in non-relativistic and relativistic regimes. Further, a connection between statistical quantities like quantal resonance-width and classical friction has been established with a classically deterministic quantity, the stability exponent of an adiabatically perturbed periodic orbit. This relation can be employed to estimate the rate of energy dissipation in finite quantum systems.
Far-field superresolution by imaging of resonance scattering
Schuster, Gerard T.
2014-10-31
We show that superresolution imaging in the far-field region of the sources and receivers is theoretically and practically possible if migration of resonant multiples is employed. A resonant multiple is one that bounces back and forth between two scattering points; it can also be the multiple between two smoothly varying interfaces as long as the reflection wave paths partially overlap and reflect from the same Fresnel zone. For a source with frequency f, compared to a one-way trip, N round trips in propagating between two scatterers increase the effective frequency by 2N × f and decrease the effective wavelength by λ/(2N). Thus, multiples can, in principle, be used as high-frequency probes to estimate detailed properties of layers. Tests with both synthetic and field data validate this claim. Improved resolution by multiple imaging is not only feasible for crustal reflections, but might be applicable to mantle and core reverberations recorded by earthquake seismologists.
Resonant scattering and diffraction beamline P09 at PETRA III
Strempfer, J.; Francoual, S.; Reuther, D.; Shukla, D. K.; Skaugen, A.; Schulte-Schrepping, H.; Kracht, T.; Franz, H.
2013-01-01
The resonant scattering and diffraction beamline P09 at PETRA III is designed for X-ray experiments requiring small beams, energy tunability, variable polarization and high photon flux. It is highly flexible in terms of beam size and offers full higher harmonic suppression. A state of the art double phase retarder setup provides variable linear or circular polarization. A high precision Psi-diffractometer and a heavy load diffractometer in horizontal Psi-geometry allow the accommodation of a ...
Resonance scattering of radio waves in the acoustically disturbed ionosphere
It is known that acoustic waves are excited in the atmosphere for a variety of reasons, including seismic oscillations of the earth's surface as a result of earthquakes, volcanic eruptions, explosions, and in the operation of other powerful sources of natural or artificial origin. When sound waves are sufficiently intense, they can create disturbances in the electron density at ionospheric heights. In this paper, we consider the properties of radio wave scattering off such disturbances created by infrasound waves, i.e., we consider Mandel'shtam-Brillouin scattering in the ionosphere. The authors discuss the possibility of a radiophysical enhancement of the effect connected with the phenomenon of resonance scattering of the radiowaves off the disturbances created in the medium by the acoustic wave
Compositeness of the Delta(1232) resonance in pi N scattering
Sekihara, Takayasu; Yamagata-Sekihara, Junko; Yasui, Shigehiro
2015-01-01
We evaluate the $\\pi N$ compositeness of the $\\Delta (1232)$ resonance so as to clarify the internal structure of $\\Delta (1232)$ in terms of the $\\pi N$ component. Here the compositeness is defined as contributions from two-body wave functions to the normalization of the total wave function and is extracted from the $\\pi N$ scattering amplitude. In this study we employ the chiral unitary approach with the interaction up to the next-to-leading order plus a bare $\\Delta$ term in chiral perturbation theory and describe $\\Delta (1232)$ in an elastic $\\pi N$ scattering. Fitting the $\\pi N$ scattering amplitude to the solution of the partial wave analysis, we obtain a large real part of the $\\pi N$ compositeness for $\\Delta (1232)$ comparable to unity and non-negligible imaginary part as well, with which we reconfirm the result in the previous study on the $\\pi N$ compositeness for $\\Delta (1232)$.
This research thesis reports the study of the mechanism of emission of alpha particles in the 11B (p, 3 α) reaction with respect to the effects of spins and parities of the various resonances met between 150 keV and 4 MeV. From an experimental point of view, the reaction has been studied by two methods: the detection of alpha particles by a semiconductor-based counter located at a given angle with respect to the beam direction and study of continuous spectra of alpha particles with respect to projectile energies, and recording, for a given resonance, of alpha-alpha coincidences by using the multi-parametric technique with two semiconductor-based sensors with a varying relative angular position. After a discussion of the main characteristics of resonance and of the mechanism of emission of alpha particles, the author first reports the theoretical study of a reaction producing three particles in the final state, and then reports the theoretical calculation of direct alpha spectrum shapes in the case of the 11B (p, 3 α) reaction (statistic hypothesis, hypothesis of interaction with two particles in the final state). The next part reports the experimental study of the 11B (p, 3 α) reaction
Resonance Scattering Mechanisms in Solids and at Solid Surfaces.
Gerber, Andrew D.
1987-09-01
The concept of resonance electron scattering is applied to two very different solid state systems, one at the surface of a solid and one in the bulk. In part I, the problem of resonance scattering of electrons from molecules adsorbed on a metallic surface is examined. An analysis is made of the factors leading to the broadening and energy shift of the e -N _{2} vibrational excitation cross sections as compared to their gas phase analogues. Two effects are found to be important: the breaking of the molecular symmetry by the surface, and the influence of the metallic image potential. Multiple scattering calculations verify that these mechanisms produce a broadening and energy shift in the range of those seen experimentally. In part II, a new mechanism is formulated for the attenuation of ultrasound in mixed valence metals. The mechanism is based on the coupling of phonons to electrons in localized, atomic-like f-levels. The local nature of the interaction gives rise to a large enhancement over the standard (Pippard) result, especially in the limit of short electron mean free path. The mechanism also produces a 'bump' in the attenuation coefficient as a function of temperature, offering an explanation for the experimentally observed 12 K feature of UPt_{3} . A calculation of the attenuation coefficient for a mixed valence lattice reveals further enhancement and structure caused by coherent absorption at f-levels in many unit cells. The effects of degeneracy and correlation are examined in a calculation of the ultrasound attenuation for a system containing dilute Kondo impurities. The unifying theme of this work is the strong interaction between electrons and vibrational modes resulting from the trapping of electrons in localized resonance states. This mechanism has previously been seen to be of great importance for electron-molecule collisions in the gas phase. In the present work, its importance is demonstrated for scattering processes in solids and at solid surfaces
12C+12C reactions at astrophysical energies: Tests of targets behaviour under beam bombardment
12C(12C,α)20Ne and 12C(12C,p)23Na are the most important reactions during the carbon burning phase in stars. Direct measurements at the relevant astrophysical energy (E=1.5±0.3MeV) are very challenging because of the extremely small cross sections involved and of the high beam-induced background originating from impurities in the targets. In addition, persistent resonant structures at low energies are not well understood and make the extrapolation of the cross section from high energy data very uncertain. As a preliminary step towards the measurements of the 12C(12C,α)20Ne and 12C(12C,p)23Na reactions we intend to investigate the behaviour of targets under beam bombardment, specifically the quantitative measurement of hydrogen and deuterium content of highly pure stable carbon targets in relation to target temperature. Experiments are taking place at the CIRCE accelerator in Caserta, Italy and preliminary results are presented here
HU Xiao-li; LIU Sa; LIU Shao-pu; LIU Zhong-fang; SONG Yan-qi
2011-01-01
In a pH=0.65-1.5 NaAc-HCI medium, methylene blue(MB) reacts with 12-tungstophosphoric acid (TPA) by virtue of electrostatic attraction and hydrophobic force to form a 3:2 ion-association complex. As a result,the intensities of resonance Rayleigh scattering(RRS), second-order scattering(SOS) and frequency doubling scattering(FDS) are enhanced greatly. The maximum scattering wavelengths of RRS, SOS and FDS are located at 316, 647 and 311 nm. The increments of scattering intensity(ΔI) are directly proportional to the concentration of MB in a certain range. The methods exhibited high sensitivity, and the detection limits(3σ) for MB are 2.3 ng/mL(RRS method),5.6 ng/mL(SOS method) and 6.4 ng/mL(FDS method), respectively. The effects of coexisting substances have been examined, and the results indicate that the methods have good selectivity. Based on the above researches, a new spectral method for the determination of trace amounts of MB has been developed. It can be applied to the determination of MB in human serum, and the recoveries are 97.5％-105.0％. The results are in good agreement with those obtained by the pharmacopoeia method. In this work, the optimum conditions of the reaction and the influencing factors were investigated. In addition, the reaction mechanism and the reasons of the enhancement of resonance light scattering were discussed.
Resonance scattering and RBS from non-stoichiometric oxides
Rutherford back scattering (RBS) and elastic nuclear resonance (non-RBS resonance scattering of 3.05 MeV α-particles from oxygen atoms of a sample, for example) have been used for non-destructive characterization of differently fired samples of cadmium oxide (a II-VI semiconductor), Bi2Sr2CaCu2O(8+x) and (Bi0.92Pb0.17)2Sr2CaCu2O(8+x) high temperature superconductors, and practically useful films of a composite of diamond nanoparticles and Si-O made by CV deposition on Si substrate. In the RBS spectrum, steps for light elements like O and Ca are practically not visible, while steps for heavy elements like Bi and Cd are clear and large. In contrast, there is a clear resonance peak due to oxygen allowing easy detection of oxygen in a sample. Most important of our present RBS findings is reduction of O-content from cadmium oxide on firing (here for 36 h) at higher and higher temperatures up to 800 deg. C. Large variations of room temperature (300 K) electrical resistivity of CdO after heat treatments at different temperatures for 36 h have been explained on basis of variation in O-content. Its room temperature resistivity of 26.4 mΩ cm for firing at 275 deg. C reduces to only 2.15 mΩ cm for firing at 800 deg. C
Delta Electroproduction in 12-C
Steven McLauchlan
2003-01-31
The Delta-nucleus potential is a crucial element in the understanding of the nuclear system. Previous electroexcitation measurements in the delta region reported a Q2 dependence of the delta mass indicating that this potential is dependent on the momentum of the delta. Such a dependence is not observed for protons and neutrons in the nuclear medium. This thesis presents the experimental study of the electroexcitation of the delta resonance in 12C, performed using the high energy electron beam at the Thomas Jefferson National Accelerator Facility, and the near 4(pie) acceptance detector CLAS that enables the detection of the full reaction final state. Inclusive, semi inclusive, and exclusive cross sections were measured with an incident electron beam energy of 1.162GeV over the Q2 range 0.175-0.475 (GeV/c)2. A Q2 dependence of the delta mass was only observed in the exclusive measurements indicating that the delta-nucleus potential is affected by the momentum of the delta.
Resonant depolarized dynamic light scattering of silver nanoplatelets
Zimbone, M., E-mail: massimo.zimbone@ct.infn.it [CNR-IMM (Italy); Messina, E. [IPCF-CNR Istituto per i Processi Chimico-Fisici (Italy); Compagnini, G.; Fragalà, M. E. [Dipartimento di Scienze Chimiche (Italy); Calcagno, L. [Dipartimento di Fisica ed Astronomia (Italy)
2015-10-15
Polarized and depolarized dynamic light scattering (DDLS) methodology was carried out on silver nanoplatelets showing strong plasmon-enhanced scattering. The hydrodynamic properties of the nanoparticles were determined by measuring the translation diffusion coefficient for “out resonant” condition and the rotational diffusion coefficient for “in resonant” condition. The results have been interpreted by applying an oblate ellipsoidal model, which allows a direct evaluation of nanoplatelets’ size and shape in agreement with scanning electron microscopy. The characterised nanoplatelets reveal a transversal size of 20 nm and a longitudinal length in the range 65–92 nm. Our investigation shows that DDLS in resonant condition is a simple and powerful technique to determine the size and shape of plasmonic nanoparticles and it can be successfully applied to characterise the dynamics of metallic nanoplatelets.
Ruel, Chris
2013-01-01
Demystifying the power of the Oracle 12c database The Oracle database is the industry-leading relational database management system (RDMS) used from small companies to the world's largest enterprises alike for their most critical business and analytical processing. Oracle 12c includes industry leading enhancements to enable cloud computing and empowers users to manage both Big Data and traditional data structures faster and cheaper than ever before. Oracle 12c For Dummies is the perfect guide for a novice database administrator or an Oracle DBA who is new to Oracle 12c. The book covers what
On the resonance structure in nucleon-nucleon scattering
Kloet, W. M.; Tjon, J. A.
1981-10-01
A possible explanation of resonance-like structure in 1D 2 and 3F 3 proton-proton phase parameters at medium energy is suggested by the analysis of an exactly soluble coupled channel model. Looping in the Argand plot is mainly due to the nucleon-delta branch cut. This effect is already present in the NΔ box diagram, but is modified by higher order multiple scattering. Poles occur close to the NΔ branch point and originate from left-hand singularities in the unphysical sheet.
Resonance Region Structure Functions and Parity Violating Deep Inelastic Scattering
Carlson, Carl E.; Rislow, Benjamin C.
2012-01-01
The primary motive of parity violating deep inelastic scattering experiments has been to test the standard model, particularly the axial couplings to the quarks, in the scaling region. The measurements can also test for the validity of models for the off-diagonal structure functions $F_{1,2,3}^{\\gamma Z}(x,Q^2)$ in the resonance region. The off-diagonal structure functions are important for the accurate calculation of the $\\gamma Z$-box correction to the weak charge of the proton. Currently, ...
Resonant electronic Raman scattering: A BCS-like system
Rodrigues, Leonarde N.; Arantes, A.; Schüller, C.; Bell, M. J. V.; Anjos, V.
2016-05-01
In this paper we investigate the resonant intersubband Raman scattering of two-dimensional electron systems in GaAs-AlGaAs single quantum wells. Self-consistent calculations of the polarized and depolarized Raman cross sections show that the appearance of excitations at the unrenormalized single-particle energy are related to three factors: the extreme resonance regime, the existence of degeneracy in intersubband excitations of the electron gas, and, finally, degeneracy in the interactions between pairs of excitations. It is demonstrated that the physics that governs the problem is similar to the one that gives rise to the formation of the superconducting state in the BCS theory of normal metals. Comparison between experiment and theory shows an excellent agreement.
Modern Theory of Gratings Resonant Scattering: Analysis Techniques and Phenomena
Sirenko, Yuriy K
2010-01-01
Diffraction gratings are one of the most popular objects of analysis in electromagnetic theory. The requirements of applied optics and microwave engineering lead to many new problems and challenges for the theory of diffraction gratings, which force us to search for new methods and tools for their resolution. In Modern Theory of Gratings, the authors present results of the electromagnetic theory of diffraction gratings that will constitute the base of further development of this theory, which meet the challenges provided by modern requirements of fundamental and applied science. This volume covers: spectral theory of gratings (Chapter 1) giving reliable grounds for physical analysis of space-frequency and space-time transformations of the electromagnetic field in open periodic resonators and waveguides; authentic analytic regularization procedures (Chapter 2) that, in contradistinction to the traditional frequency-domain approaches, fit perfectly for the analysis of resonant wave scattering processes; paramet...
Resonant Raman scattering in InGaN alloys
Davydov, V.Yu.; Goncharuk, I.N.; Smirnov, A.N.; Sakharov, A.V.; Skvortsov, A.P.; Yagovkina, M.A. [A.F. Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation); Klochikhin, A.A. [A.F. Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation); Nuclear Physics Institute, 188350 St. Petersburg (Russian Federation); Lebedev, V.M. [Nuclear Physics Institute, 188350 St. Petersburg (Russian Federation); Lu, Hai; Schaff, William J. [Department of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853 (United States)
2006-06-15
A strong resonant behavior of the Raman scattering from LO-phonons in n-InGaN alloys at excitation near the interband absorption threshold was observed. An approach has been developed to describe the resonant Raman cross sectional profile in the presence of a Burstein-Moss shift of the interband optical transitions. It has been shown that a simultaneous study of absorption, photoluminescence, and Raman spectra provides reliable information about the band gap and can be efficient for the alloy characterization. Our data show that the band gap composition dependence of InGaN is characterized by the strongly nonlinear behavior with the large bowing parameter of 2.5-2.6 eV. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Resonant soft x-ray scattering studies of buried interfaces
Resonant soft x-ray scattering (RSXS) is a unique experimental tool to access the electronic properties of buried interfaces in heterostructures that contain transition metal oxides. In this contribution, studies of SrTiO3/LaAlO3, SrTiO3/(La,Ca)MnO3 and NdGaO3/(La,Ca)MnO3 interfaces are presented. Specifically, RSXS was employed to examine the electronic reconstruction of Ti 3d and O 2p valence states at the interfaces of SrTiO3/LaAlO3 superlattices. Similarly, we used resonant soft x-ray reflectivity to investigate the electronic structure at the interfaces of SrTiO3/(La,Ca)MnO3 and NdGaO3/(La,Ca)MnO3 thin film systems.
Pion-nucleus scattering at around the DELTA (1232) resonance
The pion-nucleus scattering around 200 MeV and just above 1200 MeV is dominated by strong, broad Δ (3,3) and weak resonances in the π±N interaction. The interaction to a first approximation can be described as diffraction process. Since it is well known that the strength of the π+N and π-N interactions are quite different from each other at the resonances, the analyses of differential cross section for π+N and π-N elastic scattering data in the region of low-lying pion-nucleus resonances will be a good test of different strengths. In the present work we analyze pions scattering from nuclei 9Be, 28Si, 58Ni, 89Y and 208Pb at incident pion energies between 50 and 291 MeV within the framework of the three parameter version of the Strong Absorption Model of Frahn and Venter. All the oscillations in the elastic scattering experimental data and for the experimental angular distribution leading to 2+ and 3- collective states could be well reproduced by the model. The best fit parameter values for T, Δ and μ are determined. They are respectively the cut-off angular momentum, rounding parameter and the real nuclear phase shift parameters of the model. The interaction radius 'R', the surface diffuseness 'd' and the reaction cross-section σr have been determined from the derived parameter values. The standard nuclear radius r0 and the surface diffuseness 'd' are fairly constant. The deformation parameters βL have been determined from the normalization constant of the theory to the experiment without making any change in the elastic scattering parameters. The β2 and β3 values so extracted are in good agreement with other works. It is observed that there is hardly any difference between the values of β2 (π+) and β2 (π-) and that between β3 (π+) and β3(π-) values. (author)
Measurements and applications of neutron multiple scattering in resonance region
Capture yield of neutrons impinging on a thick material is complicated due to self-shielding and multiple scattering, especially in the resonance region. When the incident neutron energy is equal to a resonance energy of the material, capture probability of the neutron increases with sample thickness and reaches a saturation value P sub(CO). There is a simple relation between P sub(CO) and GAMMA sub(n)/GAMMA and the recoil energy by the Monte-Carlo calculation. To examine validity of the relation, P sub(CO) was measured for 19 resonances in 12 nuclides with thick samples, using a JAERI linac time-of-flight spectrometer with Moxon-Rae type gamma ray detector and transmission type neutron flux monitor. Results of the measurements confirmed the validity. With this relation, the GAMMA sub(n)/GAMMA or GAMMA sub(γ)/GAMMA value can be obtained from the measured P sub(CO), and also the level spins be determined by combining the transmission data. Because of the definition of P sub(CO), determination of the resonance parameters is not sensitive to the sample thickness as far as it is sufficiently thick. (auth.)
Constraining the 12C+12C fusion cross section for astrophysics
Bucher B.
2015-01-01
Full Text Available The 12C+12C reaction is one of the single most important nuclear reactions in astrophysics. It strongly influences late evolution of massive stars as well as the dynamics of type Ia supernovae and x-ray superbursts. An accurate estimation of the cross section at relevant astrophysical energies is extremely important for modeling these systems. However, the situation is complicated by the unpredictable resonance structure observed at higher energies. Two recent studies at Notre Dame have produced results which help reduce the uncertainty associated with this reaction. The first uses correlations with the isotope fusion systems, 12C+13C and 13C+13C, to establish an upper limit on the resonance strengths in 12C+12C. The other focuses on the specific channel 12C+12C→23Mg+n and its low-energy measurement and extrapolation which is relevant to s-process nucleosynthesis. The results from each provide important constraints for astrophysical models.
An analysis of the 12C+12C reaction using a new type of coupling potential
Full text: 12C+12C system has been one of the most extensively studied reaction so far and is a subject attracting continuous interest from both theoretical and experimental point of views. Therefore, a large body of data over a wide energy range has been accumulated for this system from the systematic studies. The previous works in the literature clearly show that the standard coupled-channel approach is inadequate to explain the problems of this rection. It can fit neither any of the individual angular distributions nor the 90 deg. elastic scattering excitation function. In our couple-channels (CC) calculations, the interaction between the 12C nuclei is described by a deformed optical potential. The real potential has the square of a Woods-Saxon shape. The imaginary potential has the standard Woods-Saxon volume shape and its depth increases quadratically with energy as: W=-2.69+0.145ELab+0.0009(ELab)2. The 12C nucleus has a static quadrupole deformation and its excitation is described within the rotational model. The empirical deformation parameter, β2=-0.6, is used in these calculations. The limitations of the standard coupled-channels method, on the one hand, and the oblate character of thr 12C and the prolate character of the compound nucleus 24Mg, on the other hand, compelled us to use a new type of coupling potential which is ablate (attractive) when two 12C nuclei are at large distances and prolate (repulsive) when they are at short distances. For the new CC case, the agreement is very good for the elastic scattering, single-2+ and mutual-2+ excitation inelastic scattering data over the whole energy range studied. The theoretical predictions of the magnitudes and the phase of the oscillations for the mutual-2+ excitation inelastic scattering data, which have been the major outstanding problems of the reaction, are in a very good agreement with the empirical values
Yuan Bo; Wen Ji-Hong; Wen Xi-Sen
2013-01-01
A locally resonant sonic material (LRSM) is an elastic matrix containing a periodic arrangement of identical local resonators (LRs),which can reflect strongly near their natural frequencies,where the wavelength in the matrix is still much larger than the structural periodicity.Due to the periodic arrangement,an LRSM can also display a Bragg scattering effect,which is a characteristic of phononic crystals.A specific LRSM which possesses both local resonance and Bragg scattering effects is presented.Via the layered-multiple-scattering theory,the complex band structure and the transmittance of such LRSM are discussed in detail.Through the analysis of the refraction behavior at the boundary of the composite,we find that the transmittance performance of an LRSM for oblique incidence depends on the refraction of its boundary and the transmission behaviors of different wave modes inside the composite.As a result,it is better to use some low-speed materials (compared with the speed of waves in surrounding medium) as the LRSM matrix for designing sound blocking materials in underwater applications,since their acoustic properties are more robust to the incident angle.Finally,a gapcoupled LRSM with a broad sub-wavelength transmission gap is studied,whose acoustic performance is insensitive to the angle of incidence.
Resonant Neutron Scattering from YBa_2Cu_3O_7
Fong, Hung Fai
1996-03-01
Recently our ( Collaborators: B. Keimer, D. Reznik, P. Bourges, I. Aksay ) study on the 41 meV magnetic resonance in YBa_2Cu_3O7 ( H. F. Fong, B. Keimer, P. W. Anderson, D. Reznik, F. Doğan, I. A. Aksay, Phy. Rev. Lett. \\underbar 75), 316 (1995) has received considerable attention. Evidence for this mode had already been collected by other groups, but our demonstration that the resonance disappears in the normal state has stimulated a large body of theoretical work. We have extended our study in several respects, using both polarized and unpolarized neutron scattering techniques. First, by calibrating the measured magnetic intensity against calculated structure factors of optical phonons and against antiferromagnetic spin waves in the same crystal after deoxygenation to YBa_2Cu_3O_6.2, we have established the absolute scale of its dynamical susceptibility \\chi''(q,ω) in the superconducting state and a limit on its magnitude in the normal state. Second, we have measured the energy and absolute spectral weight of the resonance accurately as a function of temperature. Our experimental results will be discussed in the light of recent theoretical work. Recent measurements of the high energy spin waves in the antiferromagnetic YBa_2Cu_3O_6.2 will also be reported.
Scattering resonances of ultracold atoms in confined geometries
Saeidian, Shahpoor
2008-06-18
Subject of this thesis is the investigation of the quantum dynamics of ultracold atoms in confined geometries. We discuss the behavior of ground state atoms inside a 3D magnetic quadrupole field. Such atoms in enough weak magnetic fields can be approximately treated as neutral point-like particles. Complementary to the well-known positive energy resonances, we point out the existence of short-lived negative energy resonances. The latter originate from a fundamental symmetry of the underlying Hamiltonian. We drive a mapping of the two branches of the spectrum. Moreover, we analyze atomic hyperfine resonances in a magnetic quadrupole field. This corresponds to the case for which both the hyperfine and Zeeman interaction, are comparable, and should be taken into account. Finally, we develop a general grid method for multichannel scattering of two atoms in a two-dimensional harmonic confinement. With our approach we analyze transverse excitations/deexcitations in the course of the collisional process (distinguishable or identical atoms) including all important partial waves and their couplings due to the broken spherical symmetry. Special attention is paid to suggest a non-trivial extension of the CIRs theory developed so far only for the single-mode regime and zero-energy limit. (orig.)
Scattering resonances of ultracold atoms in confined geometries
Subject of this thesis is the investigation of the quantum dynamics of ultracold atoms in confined geometries. We discuss the behavior of ground state atoms inside a 3D magnetic quadrupole field. Such atoms in enough weak magnetic fields can be approximately treated as neutral point-like particles. Complementary to the well-known positive energy resonances, we point out the existence of short-lived negative energy resonances. The latter originate from a fundamental symmetry of the underlying Hamiltonian. We drive a mapping of the two branches of the spectrum. Moreover, we analyze atomic hyperfine resonances in a magnetic quadrupole field. This corresponds to the case for which both the hyperfine and Zeeman interaction, are comparable, and should be taken into account. Finally, we develop a general grid method for multichannel scattering of two atoms in a two-dimensional harmonic confinement. With our approach we analyze transverse excitations/deexcitations in the course of the collisional process (distinguishable or identical atoms) including all important partial waves and their couplings due to the broken spherical symmetry. Special attention is paid to suggest a non-trivial extension of the CIRs theory developed so far only for the single-mode regime and zero-energy limit. (orig.)
Emission of particles in the 12 C + 12 C fusion
A fusion process analysis of the 12 C + 12 C reaction is done, using the LILITA program. The analysis consisted mainly in varying the value of the Levels density parameter, determining on this way the value of such parameter which reproduces better the contribution of the different channels of fusion-evaporation of particles for this system at different energies. Moreover a comparison with measures done in the Instituto Nacional de Investigaciones Nucleares is realized. (Author)
Observation of superconductivity in hydrogen sulfide from nuclear resonant scattering.
Troyan, Ivan; Gavriliuk, Alexander; Rüffer, Rudolf; Chumakov, Alexander; Mironovich, Anna; Lyubutin, Igor; Perekalin, Dmitry; Drozdov, Alexander P; Eremets, Mikhail I
2016-03-18
High-temperature superconductivity remains a focus of experimental and theoretical research. Hydrogen sulfide (H2S) has been reported to be superconducting at high pressures and with a high transition temperature. We report on the direct observation of the expulsion of the magnetic field in H2S compressed to 153 gigapascals. A thin (119)Sn film placed inside the H2S sample was used as a sensor of the magnetic field. The magnetic field on the (119)Sn sensor was monitored by nuclear resonance scattering of synchrotron radiation. Our results demonstrate that an external static magnetic field of about 0.7 tesla is expelled from the volume of (119)Sn foil as a result of the shielding by the H2S sample at temperatures between 4.7 K and approximately 140 K, revealing a superconducting state of H2S. PMID:26989248
Tuning Mie scattering resonances in soft materials with magnetic fields.
Brunet, Thomas; Zimny, Kevin; Mascaro, Benoit; Sandre, Olivier; Poncelet, Olivier; Aristégui, Christophe; Mondain-Monval, Olivier
2013-12-27
An original approach is proposed here to reversibly tune Mie scattering resonances occurring in random media by means of external low induction magnetic fields. This approach is valid for both electromagnetic and acoustic waves. The experimental demonstration is supported by ultrasound experiments performed on emulsions made of fluorinated ferrofluid spherical droplets dispersed in a Bingham fluid. We show that the electromagnet-induced change of droplet shape into prolate spheroids, with a moderate aspect ratio of 2.5, drastically affects the effective properties of the disordered medium. Its effective acoustic attenuation coefficient is shown to vary by a factor of 5, by controlling both the flux density and orientation of the applied magnetic field. PMID:24483797
Charge-magnetic interference resonant scattering studies of ferromagnetic crystals and thin films
The element- and site-specificity of X-ray resonant magnetic scattering (XRMS) makes it an ideal tool for furthering our understanding of complex magnetic systems. In the hard X-rays, XRMS is readily applied to most antiferromagnets where the relatively weak resonant magnetic scattering (10-2-10-6Ic) is separated in reciprocal space from the stronger, Bragg charge scattered intensity, Ic. In ferro(ferri)-magnetic materials, however, such separation does not occur and measurements of resonant magnetic scattering in the presence of strong charge scattering are quite challenging. We discuss the use of charge-magnetic interference resonant scattering for studies of ferromagnetic (FM) crystals and layered films. We review the challenges and opportunities afforded by this approach, particularly when using circularly polarized X-rays. We illustrate current capabilities at the Advanced Photon Source with studies aimed at probing site-specific magnetism in ferromagnetic crystals, and interfacial magnetism in films. (authors)
Scattering phase shift and resonance properties on the lattice: an introduction
Prelovsek, S; Mohler, D
2011-01-01
We describe the method for extracting the elastic scattering phase shift from a lattice simulation at an introductory level, for non-lattice practitioners. We consider the scattering in a resonant channel, where the resulting phase shift delta(s) allows the lattice determination of the mass and the width of the resonance from a Breit-Wigner type fit. We present the method for the example of P-wave pi-pi scattering in the rho meson channel.
Martin Freer
2014-11-01
The nucleus 12C has a rather significant role in modern nuclear physics, but whose influence can be traced to the work of Hoyle in the 1950s, when it was concluded that there should be a state close to 7.68 MeV responsible for the synthesis of carbon in stellar nucleosynthesis. Although a state at 7.65 MeV was subsequently discovered, its properties have remained something of a mystery until rather recently. This paper explores our current understanding of the structure of 12C, in particular the nature of the Hoyle state.
The use of resonance scattering of capture gamma rays as an analytical tool
The sensitivity for the resonance scattering of capture gamma rays as a tool to measure comparatively small concentrations of certain elements in bulk materials is investigated. Looking at the resonance for lead excited by iron capture gamma rays it is possible to measure concentrations down to less than 100 ppm. The advantages of the new technique are compared with other existing methods. The application of nuclear resonance scattering in prospecting for zirconium ores is emphasized
An Analysis of the $^{12}$C+$^{12}$C Reaction Using a New Type of Coupling Potential
Boztosun, I
2001-01-01
A new approach has been used to explain the experimental data for the $^{12}$C+$^{12}$C system over a wide energy range in the laboratory system from 32.0 MeV to 126.7 MeV. This new coupled-channels based approach involves replacing the usual first derivative coupling potential by a new, second-derivative coupling potential. This paper first shows and discusses the limitation of the standard coupled-channels theory in the case where one of the nuclei in the reaction is strongly deformed. Then, this new approach is shown to improve consistently the agreement with the experimental data: the elastic scattering, single-2$^{+}$ and mutual-2$^{+}$ excitation inelastic scattering data as well as their 90$^{\\circ}$ elastic and inelastic excitation functions with little energy-dependent potentials. This new approach makes major improvement on all the previous coupled-channels calculations for this system.
Polaron hopping in olivine phosphates studied by nuclear resonant scattering
Tracy, Sally June
Valence fluctuations of Fe2+ and Fe3+ were studied in a solid solution of LixFePO4 by nuclear resonant forward scattering of synchrotron x rays while the sample was heated in a diamond-anvil pressure cell. The spectra acquired at different temperatures and pressures were analyzed for the frequencies of valence changes using the Blume-Tjon model of a system with a fluctuating Hamiltonian. These frequencies were analyzed to obtain activation energies and an activation volume for polaron hopping. There was a large suppression of hopping frequency with pressure, giving an anomalously large activation volume. This large, positive value is typical of ion diffusion, which indicates correlated motions of polarons, and Li+ ions that alter the dynamics of both. In a parallel study of NaxFePO4, the interplay between sodium ordering and electron mobility was investigated using a combination of synchrotron x-ray diffraction and nuclear resonant scattering. Conventional Mossbauer spectra were collected while the sample was heated in a resistive furnace. An analysis of the temperature evolution of the spectral shapes was used to identify the onset of fast electron hopping and determine the polaron hopping rate. Synchrotron x-ray diffraction measurements were carried out in the same temperature range. Reitveld analysis of the diffraction patterns was used to determine the temperature of sodium redistribution on the lattice. The diffraction analysis also provides new information about the phase stability of the system. The temperature evolution of the iron site occupancies from the Mossbauer measurements, combined with the synchrotron diffraction results give strong evidence for a relationship between the onset of fast electron dynamics and the redistribution of sodium in the lattice. Measurements of activation barriers for polaron hopping gave fundamental insights about the correlation between electronic carriers and mobile ions. This work established that polaron-ion interactions
Elimination of Pauli resonances in the generator-coordinate description of scattering
Microscopic descriptions of elastic scattering in a cluster model with different oscillator parameters lead to the occurence of resonances without definite physical meaning, related to the almost forbidden states, known as Pauli resonances. In the generator-coordinate method, a simple basic change allows one to obtain a microscopic model free of such resonances. This technique is illustrated on α + 16O scattering. Beyond the resonance region, phase shifts change very weakly. On the contrary, bound-state and physical-resonance energies may significantly be modified. The model seems to be physically more consistent when the almost forbidden states are eliminated. (orig.)
Resonant inelastic scattering at intermediate X-ray energies
Hague, C F; Journel, L; Gallet, J J; Rogalev, A; Krill, G; Kappler, J P
2000-01-01
We describe resonant inelastic X-ray scattering (RIXS) experiments and magnetic circular dichroism (MCD) in X-ray fluorescence performed in the 3-5 keV range. The examples chosen are X-ray fluorescence MCD of FeRh and RIXS experiments performed at the L/sub 3/ edge of Ce. Fe Rh is antiferromagnetic at room temperature but has a transition to the ferromagnetic state above 400 K. The Rh MCD signal is compared with an augmented spherical wave calculation. The experiment confirms the predicted spin polarization of the Rh 4d valence states. The RIXS measurements on Ce compounds and intermetallics address the problem of mixed valency especially in systems where degeneracy with the Fermi level remains small. Examples are taken from the 2p to (4f5d) /sup +1/ followed by 3d to 2p RIXS for a highly ionic compound CeF /sub 3/ and for almost gamma -like CeCuSi. (38 refs).
Unified description of bound, resonant and scattering states
Recently we have introduced a general method for calculating the discrete Hilbert-space basis representation of the Green's operators of those Hamiltonians which have infinite symmetric tridiagonal matrix forms. The elements of this matrix are used in the calculation of the Green's matrix in terms of a three-term recurrence relation and continued fractions. We specified our general approach to the case of the Coulomb problem and the Coulomb-Sturmian basis associated with it. As a further step, we can combine this new way of calculating the Coulomb-Green's matrix with a technique of solving integral equations in discrete Hilbert-space-basis representations. This provides us with a quantum mechanical approximation method which is rather general in the sense that it is equally applicable to solving bound-, resonant- and scattering-state problems with practically any potential of physical relevance. The method is especially suited to problems where Coulomb-like asymptotics have to be treated, but the formalism also contains the case of the free Green's operator as a special case. (author)
Imaging instantaneous electron flow with ultrafast resonant x-ray scattering
Popova-Gorelova, Daria
2015-01-01
We propose a novel way to image dynamical properties of nonstationary electron systems using ultrafast resonant x-ray scattering. Employing a rigorous theoretical analysis within the framework of quantum electrodynamics, we demonstrate that a single scattering pattern from a nonstationary electron system encodes the instantaneous interatomic electron current in addition to the structural information usually obtained by resonant x-ray scattering from stationary systems. Thus, inelastic contributions that are indistinguishable from elastic processes induced by a broadband probe pulse, instead of being a concern, serve as an advantage for time-resolved resonant x-ray scattering. Thereby, we propose an approach combining elastic and inelastic resonant x-ray scattering for imaging dynamics of nonstationary electron systems in both real space and real time. In order to illustrate its power, we show how it can be applied to image the electron hole current in an ionized diatomic molecule.
Scattering of core-shell nanowires with the interference of electric and magnetic resonances.
Liu, Wei; Miroshnichenko, Andrey E; Oulton, Rupert F; Neshev, Dragomir N; Hess, Ortwin; Kivshar, Yuri S
2013-07-15
We study the scattering of normally incident waves by core-shell nanowires, which support both electric and magnetic resonances. Within such nanowires, for p-polarized incident waves, each electric resonance corresponds to two degenerate scattering channels while the magnetic resonance corresponds to only one channel. Consequently, when the electric dipole (ED) and magnetic dipole (MD) are tuned to overlap spectrally, the magnitude of the ED is twice that of the magnetic one, leading to a pair of angles of vanishing scattering. We further demonstrate that the scattering features of nanowires are polarization dependent, and vanishing scattering angles also can be induced by Fano resonances due to the interference of higher-order electric modes with the broad MD mode. PMID:23939129
Fano resonance-induced negative optical scattering force on plasmonic nanoparticles.
Chen, Huajin; Liu, Shiyang; Zi, Jian; Lin, Zhifang
2015-02-24
We demonstrate theoretically that Fano resonance can induce a negative optical scattering force acting on plasmonic nanoparticles in the visible light spectrum when an appropriate manipulating laser beam is adopted. Under the illumination of a zeroth-order Bessel beam, the plasmonic nanoparticle at its Fano resonance exhibits a much stronger forward scattering than backward scattering and consequently leads to a net longitudinal backward optical scattering force, termed Fano resonance-induced negative optical scattering force. The extinction spectra obtained based on the Mie theory show that the Fano resonance arises from the interference of simultaneously excited multipoles, which can be either a broad electric dipole mode and a narrow electric quadrupole mode, or a quadrupole and an octupole mode mediated by the broad electric dipole. Such Fano resonance-induced negative optical scattering force is demonstrated to occur for core-shell, homogeneous, and hollow metallic particles and can therefore be expected to be universal for many other nanostructures exhibiting Fano resonance, adding considerably to the flexibility of optical micromanipulation on the plasmonic nanoparticles. More interestingly, the flexible tunability of the Fano resonance by particle morphology opens up the possibility of tailoring the optical scattering force accordingly, offering an additional degree of freedom to optical selection and sorting of plasmonic nanoparticles. PMID:25635617
Effect of the third π ∗ resonance on the angular distributions for electron-pyrimidine scattering
Mašín, Zdeněk; Gorfinkiel, Jimena D.
2016-07-01
We present a detailed analysis of the effect of the well known third π∗ resonance on the angular behaviour of the elastic cross section in electron scattering from pyrimidine. This resonance, occurring approximately at 4.7 eV, is of mixed shape and core-excited character. Experimental and theoretical results show the presence of a peak/dip behaviour in this energy range, that is absent for other resonances. Our investigations show that the cause of the peak/dip is an interference of background p-wave to p-wave scattering amplitudes with the amplitudes for resonant scattering. The equivalent resonance in pyrazine shows the same behaviour and the effect is therefore likely to appear in other benzene-like molecules. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.
Magnetism in heterogeneous thin film systems: Resonant X-ray scattering studies
Kortright, J B; Bader, S D; Hellwig, O; Marguiles, D T; Fullerton, E E
2003-01-01
Magnetic and chemical heterogeneity are common in a broad range of magnetic thin film systems. Emerging resonant soft X-ray scattering techniques are well suited to resolve such heterogeneity at relevant length scales. Resonant X-ray magneto-optical Kerr effect measurements laterally average over heterogeneity but can provide depth resolution in different ways, as illustrated in measurements resolving reversible and irreversible changes in different layers of exchange-spring heterostructures. Resonant small-angle scattering measures in-plane heterogeneity and can resolve magnetic and chemical scattering sources in different ways, as illustrated in measurements of granular alloy recording media.
α + 12C rotational bands in 16O
The total quantum number N of the α + 12C rotational bands in 16O is determined by a study of α + 12C elastic scattering. The 8+ and 9- states are found around the excitation energy Ex = 30 MeV and they are the member of the known rotational bands. At the same time, the 02+ state (Ex = 6.05 MeV) is found to be dominated by N = 8. (author)
Katsuma M.
2014-03-01
Full Text Available The total quantum number N of the α+12C rotational bands in 16O is determined by a study of α+12C elastic scattering. The 8+ and 9− states are found around the excitation energy Ex = 30 MeV and they are the member of the known rotational bands. At the same time, the 02+ state (Ex = 6.05 MeV is found to be dominated by N = 8.
Microscopic description of α-cluster states in {sup 12}C
Neff, Thomas; Feldmeier, Hans [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)
2014-07-01
The structure of {sup 12}C is investigated, using both a microscopic α-cluster model and fermionic molecular dynamics (FMD) where individual nucleons are considered as degrees freedom. In the FMD calculation an effective realistic interaction derived in the unitary correlation operator method (UCOM) is employed. By explicitly including {sup 8}Be+α channels resonances and scattering states above the three-α threshold can be investigated. Of particular interest are the second 0{sup +} state, the famous Hoyle state, and the second 2{sup +} state. Monopole and quadrupole transition strengths are analyzed and compared to experiment.
New resonant inelastic X-ray scattering and coherent X-ray scattering station at UE49-SGM, BESSY II
Soft x-ray scattering techniques are powerful probes for the understanding of nano- and atomic-scale phenomena, including magnetism, atomic motion and electronic structure. New beamline UE49-SGM and experimental stations are currently under construction, dedicated to the techniques of resonant inelastic x-ray scattering (RIXS) and coherent x-ray scattering (CXS). This facility will have the unique possibility to combine high-resolution spatial information studies with high-resolution chemically- and atomically-selective spectroscopy studies for a broad range of applications.
Aharonov–Bohm effect in resonances for scattering by three solenoids
Tamura, Hideo
2015-01-01
We study how the Aharonov–Bohm effect is reflected in the location of quantum resonances for scattering by three solenoids at large separation. We also discuss what happens in the case of four solenoids.
A test of the theory of resonant scattering between analog nuclei
It has been suggested that strong resonances might be found in scattering between analog nuclei at energies near the Coulomb barrier. The authors have begun a study of such scattering for 7Be on 7Li using a 7Be beam produced with the OSU-LLNL radioactive ion beam facility. The resulting excitation function can be used to limit a combination of the strength and the width of any possible resonances
Use of nuclear resonant scattering of gamma rays for in vivo measurement of iron
Vartsky, D.; Wielopolski, L.; Ellis, K.J.; Cohn, S.H.
1981-01-01
A technique for determination of elements in human body in-vivo, utilizing nuclear resonant scattering of gamma rays has been developed. 847 keV photons emitted from a gaseous /sup 56/MnCl/sub 2/ source are resonantly scattered from /sup 56/Fe present in the body. The detection of these gamma rays is used to estimate the iron content of the liver or heart of patients. Details of the calibration procedure and potential molecular effects are described.
Evidence for Resonance Scattering in the X-ray Spectrum of Zeta Puppis
Leutenegger, Maurice
2008-01-01
We present XMM-Newton Reflection Grating Spectrometer observations of pairs of X-ray emission line profiles from the 0 star Zeta Pup that originate from the same He-like ion. The two profiles in each pair have different shapes and cannot both be consistently fit by models assuming the same wind parameters. We show that the differences in profile shape can be accounted for in a model including the effects of resonance scattering, which affects the resonance line in the pair but not the intercombination line. This implies that resonance scattering is also important in single resonance lines, where its effect is difficult to distinguish from a low effective continuum optical depth in the wind. Thus, resonance scattering may help reconcile X-ray line profile shapes with literature mass-loss rates.
Resonance scattering in the X-ray emission line profiles of Zeta Puppis
Leutenegger, M A; Kahn, S M; Owocki, S P; Paerels, F B S
2007-01-01
We present XMM-Newton Reflection Grating Spectrometer observations of pairs of X-ray emission line profiles from the O star Zeta Pup that originate from the same He-like ion. The two profiles in each pair have different shapes and cannot both be consistently fit by models assuming the same wind parameters. We show that the differences in profile shape can be accounted for in a model including the effects of resonance scattering, which affects the resonance line in the pair but not the intercombination line. This implies that resonance scattering is also important in single resonance lines, where its effect is difficult to distinguish from a low effective continuum optical depth in the wind. Thus, resonance scattering may help reconcile X-ray line profile shapes with literature mass-loss rates.
Shamsudeen, Riyaj; Yu, Kai; Farooq, Tariq
2013-01-01
Expert Oracle RAC 12c is a hands-on book helping you understand and implement Oracle Real Application Clusters (RAC), and to reduce the total-cost-of-ownership (TCO) of a RAC database. As a seasoned professional, you are probably aware of the importance of understanding the technical details behind the RAC stack. This book provides deep understanding of RAC concepts and implementation details that you can apply toward your day-to-day operational practices. You'll be guided in troubleshooting and avoiding trouble in your installation. Successful RAC operation hinges upon a fast-performing netwo
The limitations of resonant Compton scattering as a gamma-ray burst model
Brainerd, J. J.
1992-01-01
Resonant Compton upscattering is commended as a mechanism that produces a hard gamma-ray spectrum while suppressing X-rays. This model, however, has severe physical and observational limitations. Effective X-ray suppression places a lower limit on the electron density; above this limit X-rays scatter multiple times, so the single-scattering approximation of this mechanism is invalid. Multiple scattering produces a spectrum that is much harder than the single-scattering spectrum. As the Thomson optical depth of a power-law electron beam approaches unity, photon spawning commences at a high rate and physically invalidates the underlying electron distribution. The Compton upscattering model is therefore only valid over a narrow range of electron densities. An observational consequence of this model is the absence of the third cyclotron resonance. Resonant scattering produces gamma-rays that propagate nearly along the magnetic field. The resonant cross section of the third harmonic, which is strongly angle dependent, falls below the Compton continuum for these gamma rays. The observation of a third cyclotron resonance in a gamma-ray burst spectrum would eliminate resonant Compton scattering as a gamma-ray burst process.
Xue, Jin-Hua; Qian, Qiu-Mei; Wang, Yong-Sheng; Meng, Xia-Ling; Liu, Lu
2013-02-01
A novel method of resonance light scattering (RLS) was developed for the analysis of trace metallothioneins (MTs) in human urine. In a CH3COOH-CH3COONa buffer solution of pH 4.5, the formation of a complex between levofloxacin (LEV)-Pd and MTs led to enhance the RLS intensity of the system, and the enhanced RLS intensity at 468 nm was proportional to the concentration of MTs in the range of 0.059-22.4 μg mL-1. The linear regression equation was ΔI = 127.5 ρ (μg mL-1)-88.02 with a correlation coefficient of 0.9992, and the detection limit of 17.8 ng mL-1. The relative standard deviation and the average recovery were 3.8-5.4% (n = 11) and 92.15%, respectively. The proposed method is convenient, reliable and sensitive, and has been used successfully for the determination of trace MTs in human urine samples.
Angular dependence of resonant inelastic x-ray scattering : A spherical tensor expansion
Juhin, Amelie; Brouder, Christian; de Groot, Frank
2014-01-01
A spherical tensor expansion is carried out to express the resonant inelastic scattering cross-section as a sum of products of fundamental spectra with tensors involving wavevectors and polarization vectors of incident and scattered photons. The expression presented in this paper differs from that o
Sub-Coulomb fusion excitation function for 12 C + 12 C
Fusion excitation functions are measured for the o, p and n evaporation channels in the fusion of the 12 C + 12 C system at center of mass energies between 4.5 and 6.5 MeV, with energy steps of 75 keV. The X-ray technique is used with a new absolute normalization method which is independent of charge collection and allows at the same time to monitor the Carbon buildup on the target. Good agreement is obtained with absolute cross section values previously measured using particle detection techniques, but smaller energy steps are used in the present experiment. As in previous works much structure is seen in the excitation function which is consistent with the positions of resonances reported in the literature for this system. (Author)
Resonant inelastic X-ray scattering of liquid water
Highlights: ► Two peaks are observed in the lone pair region of the XES spectrum of water assigned to tetrahedral and distorted hydrogen bonding configurations. ► The isotope effect observed as different relative peak heights is due to spectral line shape differences. ► The two different hydrogen bonding environments can be related to local structures mimicking either low density water or high density water. -- Abstract: We review recent studies using resonant inelastic X-ray scattering (RIXS) or also here denoted X-ray emission spectroscopy (XES) on liquid water and the assignment of the two sharp peaks in the lone-pair region. Using the excitation energy dependence we connect the two peaks to specific features in the X-ray absorption (XAS) spectrum which have independently been assigned to molecules in tetrahedral or distorted configurations. The polarization dependence shows that both peaks are of 1b1 origin supporting an interpretation in terms of two structural species, tetrahedral or disordered, which is furthermore consistent with the temperature-dependence of the two peaks. We discuss effects of life-time vibrational interference and how this affects the two components differently and also leads to differences in the relative peak heights for H2O and D2O. We show furthermore that the inherent structure in molecular dynamics simulations contain the structural bimodality suggested by XES, but this is smeared out in the real structure when temperature is included. We present a discussion around alternative interpretations suggesting that the origin of the two peaks is related to ultrafast dissociation and show evidence that such a model is inconsistent with several experimental observations and theoretical concepts. We conclude that the peaks reflect a temperature-dependent balance in fluctuations between tetrahedral and disordered structures in the liquid. This is well-aligned with theories of water under supercooled conditions and higher pressures
Experimental evidence for dual diffractive resonances in pion-nucleus scattering
Experimental data on the pion-nucleus total cross sections are analysed in terms of the dual diffractive resonance (DDR) mechanism. The DDR predictions are found to agree well with the actual experimental data in the region corresponding to the Δ(1236) resonance in elementary πN scattering. (orig.)
Triple-resonant Brillouin light scattering in magneto-optical cavities
Haigh, J A; Ramsay, A J; Ferguson, A J
2016-01-01
An enhancement in Brillouin light scattering of optical photons with magnons is demonstrated in magneto-optical whispering gallery mode resonators tuned to a triple resonance point. This occurs when both the input and output optical modes are resonant with those of the whispering gallery resonator, with a separation given by the ferromagnetic resonance (FMR) frequency. The identification and excitation of specific optical modes allows us to gain a clear understanding of the mode-matching conditions. A selection rule due to wavevector matching leads to an intrinsic single-sideband excitation. Strong suppression of one sideband is essential for one-to-one frequency mapping in coherent optical-to-microwave conversion.
Resonant Bound-Free Contributions to Thomson Scattering of X-rays by Warm Dense Matter
Johnson, W R; Cheng, K T
2013-01-01
Recent calculations [Nilsen et al. arXiv:1212.5972] predict that contributions to the scattered photon spectrum from 3s and 3p bound states in chromium (Z=24) at metallic density and T=12 eV resonate below the respective bound-state thresholds. These resonances are shown to be closely related to continuum lowering, where 3d bound states in the free atom dissolve into a resonant l=2 partial wave in the continuum. The resulting d-state resonance dominates contributions to the bound-free dynamic structure function, leading to the predicted resonances in the scattered X-ray spectrum. Similar resonant features are shown to occur in all elements in the periodic table between Ca and Mn (20 <= Z <= 25).
Effects of up scattering by heavy nuclides on Doppler changes of resonance adsorption
A procedure for handling energy changes of neutrons accurately in a Monte Carlo code, within the large resonances of heavy nuclides, is discussed. The procedure has been applied in the MCNP program to sample problem which relates to PWR unit cells. The statistical uncertainties in estimating the effect of neutron up scattering in pronounced resonances of heavy nuclides on resonance absorption rates, and their temperature changes, are discussed. (author). 10 refs
Stability of Complex-Rotation Method on a Simple Resonant Scattering Problem
SHEN Li; WANG Lei; LIU Xiao-Jun; SHI Ting-Yun; LIU Hong-Ping
2008-01-01
@@ The stability of the complex-rotation method in B-spline basis for a simple atomic resonant scattering problem in free field is investigated. The numerical calculation shows that this method has a feature that the solution will not change in a wide range of rotation angle θ. Our determined scattering resonant energies and widths exactly coincide with the popularly accepted values. A new resonance is identified numerically although it is very broad.The norm of the complex eigenvalue, [E], is proposed to investigate and to evaluate the stability of the obtained complex eigenvalues.
Resonances and higher twist in polarized lepton-nucleon scattering
Edelmann, J; Kaiser, N; Weise, W
2000-01-01
We present a detailed analysis of resonance contributions in the context of higher twist effects in the moments of the proton spin structure function g_1. For each of these moments, it is found that there exists a characteristic Q^2 region in which (perturbative) higher twist corrections coexist with (non-perturbative) resonance contribution of comparable magnitude.
Evidence for dibaryon resonances in nucleon-nucleon scattering
There has been a revival of interest in the subject of nucleon-nucleon resonances in the past 3 to 4 years, largely generated by experimental results from the polarized beam program at the Argonne ZGS. Evidence from experimental results and phase shift and phenomenological analyses incorporating these results regarding the existence of these resonances is summarized. 20 figures
Double-confocal resonator for X-ray generation via intracavity Thomson scattering
Xie, M. [Lawrence Berkeley Lab., CA (United States)
1995-12-31
There has been a growing interest in developing compact X-ray sources through Thomson scattering of a laser beam by a relativistic electron beam. For higher X-ray flux it is desirable to have the scattering to occur inside an optical resonator where the laser power is higher. In this paper I propose a double-confocal resonator design optimized for head-on Thomson scattering inside an FEL oscillator and analyze its performance taking into account the diffraction and FEL gain. A double confocal resonator is equivalent to two confocal resonators in series. Such a resonator has several advantages: it couples electron beam through and X-ray out of the cavity with holes on cavity mirrors, thus allowing the system to be compact; it supports the FEL mode with minimal diffraction loss through the holes; it provides a laser focus in the forward direction for a better mode overlap with the electron beam; and it provides a focus at the same location in the backward direction for higher Thomson scattering efficiency; in addition, the mode size at the focal point and hence the Rayleigh range can be adjusted simply through intracavity apertures; furthermore, it gives a large mode size at the mirrors to reduce power loading. Simulations as well as analytical results will be presented. Also other configurations of intracavity Thomson scattering where the double-confocal resonator could be useful will be discussed.
Imaging interatomic electron current in crystals with ultrafast resonant x-ray scattering
Popova-Gorelova, Daria
2015-01-01
We demonstrate how the technique of ultrafast resonant x-ray scattering can be applied to imaging dynamics of electronic wave packets in crystals. We study scattering patterns from crystals with electron dynamics in valence bands taking into account that inelastic and elastic scattering events induced by a broad-band probe pulse cannot be separated through the spectroscopy of the scattered photon. As a result, scattering patterns are not determined by the structure factor at the time of measurement, but can encode the instantaneous electron current between scattering atoms. We provide examples of how the interatomic electron current in a periodic structure can be extracted from a single scattering pattern by considering valence electron hole motion in (KBr)$_{108}$ and Ge$_{83}$ clusters.
Resonance scattering, absorption and off-centre abundance peaks in clusters of galaxies
Sanders, J S
2006-01-01
A possible explanation for the central abundance dips found from spatially-resolved X-ray spectroscopy of several groups and clusters of galaxies is resonance scattering. A number of the prominent iron emission lines are resonance lines. We construct a unique spectral model which takes account of resonance scattering for several thousand resonance lines, projection effects, photoelectric absorption, and allows direct spectral fitting. We apply our model to Chandra observations of two clusters with pronounced central abundance dips, Centaurus and Abell 2199. The results show that the effect of resonance scattering on emission from the centre of the cluster can be as much as 30 per cent for the Fe-K resonance lines, and 10 per cent for several Fe-L lines, if turbulence is low. The change to the metallicities obtained by fitting low resolution CCD spectra is at most 10 per cent. Accounting for resonance scattering does not remove the central dip. Allowing for internal absorption within the Centaurus significantl...
Baron, A.Q.R.
1995-04-01
This thesis explores resonant nudear scattering of synchrotron radiation. An introductory chapter describes some useful concepts, such as speedup and coherent enhancement, in the context of some basic physical principles. Methods of producing highly monochromatic synchrotron beams usmg either electronic or nuclear scattering are also discussed. The body of the thesis concentrates on detector development and specular scattering from iynthetic layered materials. A detector employing n-dcrochannel plate electron multipliers is shown to have good ({approximately}50%) effidency for detecting 14.4 key x-rays incident at small ({approximately}0.5 degree) grazing angles onto Au or CsI photocathodes. However, being complicated to use, it was replaced with a large area (>=lan2) avalanche photodiode (APD) detector. The APD`s are simpler to use and have comparable (30--70%) efficiencies at 14.4 key, subnanosecond time resolution, large dynan-dc range (usable at rates up to {approximately}10{sup 8} photons/second) and low (<{approximately}0.01 cts/sec) background rates. Maxwell`s equations are used to derive the specular x-ray reflectivity of layered materials with resonant transitions and complex polarization dependencies. The effects of interfadal roughness are treated with some care, and the distorted wave Born approximation (DWBA) used to describe electronic scattering is generalized to the nuclear case. The implications of the theory are discussed in the context of grazing incidence measurements with emphasis on the kinematic and dynamical aspects of the scattering.
Implications of the ABC Resonance Structure on Elastic Neutron-Proton Scattering
Pricking, Annette; Clement, H
2013-01-01
In recent WASA-at-COSY measurements of the basic double-pionic fusion reactions $pn \\to d\\pi^0\\pi^0$ and $pn \\to d\\pi^+\\pi^-$ a narrow resonance structure with $I(J^P) = 0(3^+)$ in the total cross section has been found. If this constitutes a s-channel resonance in the $pn$ system, then it should cause distinctive consequences in $pn$ scattering. The magnitude of the decay width into the $pn$ channel is estimated and the expected resonance effects in integral and differential $pn$ scattering observables are presented. The inclusion of the resonance improves the description of total cross section data. For the analyzing power a characteristic energy dependence is predicted, which should allow a crucial experimental check of the resonance hypothesis.
Narrow Near-Threshold Resonance in e+-He+ Scattering
LIU Min-Min; HAN Hui-Li; GU Si-Hong; SHI Ting-Yun
2012-01-01
An independent alternative calculation is performed for narrow near-threshold resonances in the e+-He+ system using the stabilization method in the framework of hyperspherical coordinates (HSSM).A narrow resonance at Er =-0.249995 with width T =1.9 × 10-5,associated with the He2+-Ps(n =1) threshold is confirmed.The resonances around the energies -0.365 and -0.195,predicted by Bhatia and Drachman [Phys.Rev.A 42 (1990)5117] and confirmed by Ho [Phys.Rev.A 53 (1996)3165],do not appear in our calculations.%An independent alternative calculation is performed for narrow near-threshold resonances in the e+-He+ system using the stabilization method in the framework of hyperspherical coordinates (HSSM). A narrow resonance at Er = -0.249995 with width r = 1.9 x 10-5, associated with the He2+-Ps(n = 1) threshold is confirmed. The resonances around the energies -0.365 and -0.195, predicted by Bhatia and Drachman [Phys. Rev. A 42(1990)5117] and confirmed by Ho [Phys. Rev. A 53 (1996) 3165], do not appear in our calculations.
Chaotic scattering in the presence of a dense set of overlapping Feshbach resonances
Jachymski, Krzysztof
2015-01-01
Complex quantum systems consisting of large numbers of strongly coupled states exhibit characteristic correlations in the level spacing distribution which can be described by Random Matrix Theory. Scattering resonances observed in ultracold atomic and molecular systems exhibit similar features as a consequence of their energy level structure. We study how the overlap between Feshbach resonances affects the distribution of resonance spacings. We find that the level repulsion between resonances leads to correlations that resemble the results known for quantum chaotic systems even when the assumptions of Random Matrix Theory are not fulfilled.
Resonant Bound-Free Contributions to Thomson Scattering of X-rays by Warm Dense Matter
Johnson, W. R.; Nilsen, J.; Cheng, K. T.
2013-01-01
Recent calculations [Nilsen et al. arXiv:1212.5972] predict that contributions to the scattered photon spectrum from 3s and 3p bound states in chromium (Z=24) at metallic density and T=12 eV resonate below the respective bound-state thresholds. These resonances are shown to be closely related to continuum lowering, where 3d bound states in the free atom dissolve into a resonant l=2 partial wave in the continuum. The resulting d-state resonance dominates contributions to the bound-free dynamic...
Non-central interactions in 12C(p,p')12C*(1+; 15.11 MeV)
Spin dependent non-central interactions were introduced into nuclear physics when Schwinger proposed the NN tensor interaction to explain the observed quadrupole moment of the deuteron. The present paper discusses the nature of non-central forces that come into play in inelastic scattering of nucleons on 12C
Scattering of electromagnetic pulses by metal nanospheres in the vicinity of a Fano-like resonance
Astapenko, V. A.; Svita, S. Yu.
2015-06-01
In the work, radiation scattering by metal nanospheres in a dielectric matrix in case of ultrashort and long electromagnetic pulses is studied theoretically. Spectral efficiencies of backward and forward scattering by silver nanospheres in glass are calculated with the use of experimental data on the dielectric permittivity of silver. The presence of Fano-like resonances in spectral dependences of scattering efficiency caused by interference of dipole and quadrupole scatterings is shown. Backward and forward scattering of ultrashort pulses is calculated and analyzed. The obtained dependences of the total probability of scattering (during all time of the action of a pulse) on pulse duration demonstrate an essential distinction between an ultrashort case and a long pulse limit.
Scattering of electromagnetic pulses by metal nanospheres in the vicinity of a Fano-like resonance
Astapenko, V.A.; Svita, S.Yu., E-mail: sergey.svita@gmail.com
2015-06-26
In the work, radiation scattering by metal nanospheres in a dielectric matrix in case of ultrashort and long electromagnetic pulses is studied theoretically. Spectral efficiencies of backward and forward scattering by silver nanospheres in glass are calculated with the use of experimental data on the dielectric permittivity of silver. The presence of Fano-like resonances in spectral dependences of scattering efficiency caused by interference of dipole and quadrupole scatterings is shown. Backward and forward scattering of ultrashort pulses is calculated and analyzed. The obtained dependences of the total probability of scattering (during all time of the action of a pulse) on pulse duration demonstrate an essential distinction between an ultrashort case and a long pulse limit.
Scattering of electromagnetic pulses by metal nanospheres in the vicinity of a Fano-like resonance
In the work, radiation scattering by metal nanospheres in a dielectric matrix in case of ultrashort and long electromagnetic pulses is studied theoretically. Spectral efficiencies of backward and forward scattering by silver nanospheres in glass are calculated with the use of experimental data on the dielectric permittivity of silver. The presence of Fano-like resonances in spectral dependences of scattering efficiency caused by interference of dipole and quadrupole scatterings is shown. Backward and forward scattering of ultrashort pulses is calculated and analyzed. The obtained dependences of the total probability of scattering (during all time of the action of a pulse) on pulse duration demonstrate an essential distinction between an ultrashort case and a long pulse limit
Pion-nucleon scattering around the delta resonance
Long, Bingwei
2009-01-01
We develop a generalized version of heavy-baryon chiral perturbation theory to describe pion-nucleon scattering in a kinematic domain that extends continuously from threshold to the delta-isobar peak. The $P$-wave phase shifts are used to illustrate this framework.
Nucleon Resonances in Meson Nucleon Scattering with Strangeness Production
Waluyo, A.; Bennhold, C.; Haberzettl, H.; Penner, G.; Mosel, U.; Mart, T.
2000-01-01
An effective Lagrangian model in a coupled channels framework is applied to extract nucleon resonance parameters. In the K-matrix approximation, we simultaneously analyze all the available data for the transitions from pi N to five possible meson-baryon final states, pi N, pipi N, eta N, K Lambda, and KSigma, in the energy range from pi N threshold up to W = 2 GeV. In this work, we focus our efforts on the K Sigma channel. In particular, we include a set of Delta resonances around 1900 MeV: t...
φ(1020) f0(980) S-wave scattering and the Y(2175) resonance
We have studied the φ(1020)f0(980) S-wave scattering at energies around threshold employing chiral Lagrangians coupled to vector mesons through minimal coupling. The interaction kernel is obtained by considering the f0(980) as a KK bound state. The Y(2175) resonance is generated in this approach by the self-interactions between the φ(1020) and the f0(980) resonances. We are able to describe the e+e-→φ(1020)f0(980) recent scattering data to test experimentally our scattering amplitudes, concluding that the Y(2175) resonance has a large φ(1020)f0(980) meson-meson component.
Multi-Channel Atomic Scattering and Confinement-Induced Resonances in Waveguides
Saeidian, Shahpoor; Schmelcher, Peter
2008-01-01
We develop a grid method for multi-channel scattering of atoms in a waveguide with harmonic confinement. This approach is employed to extensively analyze the transverse excitations and deexcitations as well as resonant scattering processes. Collisions of identical bosonic and fermionic as well as distinguishable atoms in harmonic traps with a single frequency $\\omega$ permitting the center-of-mass (c.m.) separation are explored in depth. In the zero-energy limit and single mode regime we reproduce the well-known confinement-induced resonances (CIRs) for bosonic, fermionic and heteronuclear collisions. In case of the multi-mode regime up to four open transverse channels are considered. Previously obtained analytical results are extended significantly here. Series of Feshbach resonances in the transmission behaviour are identified and analyzed. The behaviour of the transmission with varying energy and scattering lengths is discussed in detail. The dual CIR leading to a complete quantum suppression of atomic sca...
Khlebtsov, Boris N.; Khlebtsov, Nikolai G.
2006-07-01
Recently, Chen et al. [J. Biomed. Opt. Vol. 10, 024005 (2005)] reported on the concept of multicolor molecular imaging, which uses resonant light-scattering spectroscopy of multilayer nanospheres. They claimed that the resonance scattering peaks of three-layer nanoshells can be designed so that the ultrasharp widths are as narrow as 10 nm. Here we show that such ultrasharp labels cannot be fabricated in reality because the effects of size-dependent dielectric functions result in the five- to tenfold broadening of resonant scattering peaks. Furthermore, contrary to the data of Chen et al., we did not find any significant advantages of three-layer structures, as compared with the usual silica/metal nanoshells.
Experimental elucidation: microscopic mechanism of resonant X-ray scattering in manganite films
Ohsumi, H; Kiyama, T
2003-01-01
Resonant X-ray scattering experiments have been performed on perovskite manganite La sub 0 sub . sub 5 Sr sub 0 sub . sub 5 MnO sub 3 thin films, which are grown on three distinct perovskite with a coherent epitaxial strain and have a forced ferro-type orbital ordering of Mn 3d orbitals. Using an interference technique, we have successfully observed the resonant X-ray scattering signal from the system having the ferro-type orbital ordering and also revealed the energy scheme of Mn 4p bands. For the forced ferro-type orbital ordering system, the present results evidence that the resonant X-ray scattering signal originates from the band structure effect due to the Jahn-Teller distortion of a MnO sub 6 octahedron, and not from the Coulomb interaction between 3d and 4p electrons. (author)
Studies of reaction mechanism in 12C + 12C system at intermediate energy of 28.7 MeV/N
The reaction mechanism in 12C + 12C system at intermediate energy of about 30 MeV/nucleon was studied. The contribution of various reaction mechanisms (inelastic scattering, transfer reactions, compound nucleus reactions, sequential decay following inelastic excitation and transfer) to the total reaction cross section were found. The analysis of inclusive and coincidence spectra shows that sequential fragmentation processes dominate
Coherent Scattering of Near-Resonant Light by a Dense Microscopic Cold Atomic Cloud
Jennewein, S.; Besbes, M.; Schilder, N. J.; Jenkins, S. D.; Sauvan, C.; Ruostekoski, J.; Greffet, J.-J.; Sortais, Y. R. P.; Browaeys, A.
2016-06-01
We measure the coherent scattering of light by a cloud of laser-cooled atoms with a size comparable to the wavelength of light. By interfering a laser beam tuned near an atomic resonance with the field scattered by the atoms, we observe a resonance with a redshift, a broadening, and a saturation of the extinction for increasing atom numbers. We attribute these features to enhanced light-induced dipole-dipole interactions in a cold, dense atomic ensemble that result in a failure of standard predictions such as the "cooperative Lamb shift". The description of the atomic cloud by a mean-field model based on the Lorentz-Lorenz formula that ignores scattering events where light is scattered recurrently by the same atom and by a microscopic discrete dipole model that incorporates these effects lead to progressively closer agreement with the observations, despite remaining differences.
Resonant Raman scattering in GaSe and GaS/sub x/Se/sub 1-x/
Chiang, T.C.; Camassel, J.; Voitchovsky, J.P.; Shen, Y.R.
1976-07-01
Multiphonon resonant Raman scattering up to four phonons in GaSe and one and two phonon resonant Raman scattering in the mixed GaS/sub x/Se/sub 1 - x/ crystals with x less than or equal to 0.23 were investigated. The results can be explained by a simple theory in which the dispersion of the resonance behavior is mainly dominated by resonances with the 1s direct exciton state.
New formula for a resonant scattering near an inelastic threshold
We show that the Flatte formula is not adequate to interpret precision data on a resonance production near an inelastic threshold. A unitary parameterization, satisfying generalized Watson's theorem for the production amplitudes, is proposed to replace the Flatte parameterization in the phenomenological analyses of the experimental data
The elastic π-nucleus scattering in the (3/2-3/2) resonance region
The elastic pion-nucleus scattering in the (3/2-3/2) resonance region is analyzed. The aim of the work is threefold. Working with the Watson's multiple scattering theory, one strives for: -a better understanding of the pion-nucleus interaction in terms of elementary interaction; -a justification of the theoretical framework by using the Lee model; -a study of the sensitivity of the optical potential to the macroscopic parameters of the nucleus
Li Li; Wen Ji-Hong; Cai Li; Zhao Hong-Gang; Wen Xi-Sen
2013-01-01
Using the multilayered cylinder model,we study acoustic scattering from a submerged cylindrical shell coated with locally resonant acoustic metamaterials,which exhibit locally negative effective mass densities.A spring model is introduced to replace the traditional transfer matrix,which may be singular in the negative mass region.The backscattering form function and the scattering cross section are calculated to discuss the acoustic properties of the coated submerged cylindrical shell.
Angular dependence of resonant inelastic x-ray scattering: a spherical tensor expansion
Juhin Amélie; Brouder Christian; Groot Frank
2013-01-01
International audience A spherical tensor expansion is carried out to express the resonant inelastic scattering cross-section as a sum of products of fundamental spectra with tensors involving wavevectors and polarization vectors of incident and scattered photons. The expression presented in this paper differs from that of the influential article by Carra et al. (Phys. Rev. Lett. 74, 3700, 1995) because it does not omit interference terms between electric dipole and quadrupole contribution...
Using the multilayered cylinder model, we study acoustic scattering from a submerged cylindrical shell coated with locally resonant acoustic metamaterials, which exhibit locally negative effective mass densities. A spring model is introduced to replace the traditional transfer matrix, which may be singular in the negative mass region. The backscattering form function and the scattering cross section are calculated to discuss the acoustic properties of the coated submerged cylindrical shell. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Nanometer-range atomic order directly recovered from resonant diffuse scattering
Kopecký, Miloš; Kub, Jiří; Fábry, Jan; Hlinka, Jiří
2016-01-01
Roč. 93, č. 5 (2016), "054202-1"-"054202-8". ISSN 1098-0121 R&D Projects: GA ČR GA15-04121S Institutional support: RVO:68378271 Keywords : diffuse scattering * resonant scattering * atomic structure * perovskites * relaxors * PbMg 1/3 Nb 2/3 O 3 (PMN) Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.736, year: 2014
International workshop on resonant X-ray scattering in electrically-ordered systems
The research field of Resonant X-ray Scattering (RXS) has achieved tremendous progress in the last years. Nowadays RXS is rapidly becoming the crucial technique for investigating the subtleties of microscopic magnetism in systems where the ground state properties reflect a delicate balance between several different correlated processes. The aim of this workshop is to discuss present and future possibilities for RXS investigations of electronic order, including studies of charge, magnetic, and multipolar ordered states. The sessions will cover experimental and theoretical aspects of hard and soft X-ray resonant scattering from single crystals and thin films. This document gathers the summaries of the presentations
Resonant scattering experiments with radioactive nuclear beams - Recent results and future plans
Teranishi, T.; Sakaguchi, S. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 (Japan); Uesaka, T.; Kubono, S.; Wakabayashi, Y. [RIKEN Nishina Center, 2-1 Hirosawa Wako, Saitama 351-0198 (Japan); Yamaguchi, H.; Kurihara, Y.; Bihn, D. N.; Kahl, D.; Watanabe, S. [Center for Nuclear Study (CNS), University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hashimoto, T. [Center for Nuclear Study (CNS), University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan and Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); Hayakawa, S. [Center for Nuclear Study (CNS), University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan and Istituto Nazionale di Fisica Nucleare, Laboratori Nationali del Sud (INFN-LNS), via S.Sofia 62, Catania, 95125 (Italy); Khiem, L. H.; Cuong, P. V. [Institute of Physics, Vietnam Academy for Science and Technology, 10 Daotan, Badinh, Hanoi (Viet Nam); Goto, A. [RIKEN Nishina Center, 2-1 Hirosawa Wako, Saitama 351-0198, Japan and National Insitute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Chiba-shi, 263-8555 (Japan)
2013-04-19
Resonant scattering with low-energy radioactive nuclear beams of E < 5 MeV/u have been studied at CRIB of CNS and at RIPS of RIKEN. As an extension to the present experimental technique, we will install an advanced polarized proton target for resonant scattering experiments. A Monte-Carlo simulation was performed to study the feasibility of future experiments with the polarized target. In the Monte-Carlo simulation, excitation functions and analyzing powers were calculated using a newly developed R-matrix calculation code. A project of a small-scale radioactive beam facility at Kyushu University is also briefly described.
International workshop on resonant X-ray scattering in electrically-ordered systems
Collins, S.P.; Pettifer, R.F.; Laundy, D.; Ishida, K.; Kokubun, J.; Giles, C.; Yokaichiya, F.; Song, C.; Lee, K.B.; Ji, S.; Koo, J.; Park, Y.J.; Kim, J.Y.; Park, J.H.; Shin, H.J.; Rhyee, J.S.; Oh, B.H.; Cho, B.K.; Wilkins Stuart, B.; Paixao, J.A.; Caciuffo, R.; Javorsky, P.; Wastin, F.; Rebizant, J.; Detlefs, C.; Bernheoft, N.; Lander, G.H.; Bombardi, A.; Bergevin, F. de; Matteo, S. di; Paolasini, L.; Rodriguez-Carvajal, J.; Carretta, P.; Millet, P.; Caciuffo, R.; Goff, J.P.; Deen, P.P.; Lee, S.; Stunault, A.; Brown, S.; Mannix, D.; McIntyre, G.J.; Ward, R.C.C.; Wells, M.R.; Lorenzo, J.E.; Joly, Y.; Nazarenko, E.; Staub, U.; Srajer, G.; Haskel, D.; Choi, Y.; Lee, D.R.; Lang, J.C.; Meersschaut, J.; Jiang, J.S.; Bader, S.D.; Bouchenoire, L.; Brown, S.D.; Beesley, A.; Herring, A.; Thomas, M.; Thompson, P.; Langridge, S.; Stirling, W.G.; Mirone, A.; Lander, G.; Wilkins, S.; Ward, R.C.C.; Wells, M.R.; Zochowski, S.W.; Garcia, J.; Subias, G.; Blasco, J.; Sanchez, M.C.; Proietti, M.G.; Lovesey, S.W.; Dmitrienko, V.E.; Ovchinnikova, E.N.; Ishida, K.; Kokubun, J.; Kirfel, A.; Collins, S.P.; Laundy, D.; Oreshko, A.P.; Strange, P.; Horne, M.; Arola, E.; Winter, H.; Szotek, Z.; Temmerman, W.M.; Igarashi, J.; Usuda, M.; Takahashi, M.; Matteo, S. di; Bernhoeft, N.; Hill, J.P.; Lang, J.C.; McWhan, D.; Lee, D.R.; Haskel, D.; Srajer, G.; Hatton Peter, D.; Katsumata, K.; Braithwaite, D
2004-07-01
The research field of Resonant X-ray Scattering (RXS) has achieved tremendous progress in the last years. Nowadays RXS is rapidly becoming the crucial technique for investigating the subtleties of microscopic magnetism in systems where the ground state properties reflect a delicate balance between several different correlated processes. The aim of this workshop is to discuss present and future possibilities for RXS investigations of electronic order, including studies of charge, magnetic, and multipolar ordered states. The sessions will cover experimental and theoretical aspects of hard and soft X-ray resonant scattering from single crystals and thin films. This document gathers the summaries of the presentations.
de Escobar, Y N Martinez; Yan, M; Killian, T C
2009-01-01
We demonstrate control of the scattering properties of atomic strontium with an optical Feshbach resonance near the 1S0-3P1 intercombination transition at 689 nm. Significant changes in scattering length on the order of plus/minus 10 a0 can be achieved at large detuning (~10e6 linewidths), and we are able to increase phase space density through enhanced evaporative cooling. Loss rate constants are at least two orders of magnitude smaller than in previous experiments with optical Feshbach resonances, but are three orders of magnitude larger than predicted.
Direct probe of anisotropy in atom-molecule collisions via quantum scattering resonances
Klein, Ayelet; Skomorowski, Wojciech; Żuchowski, Piotr S; Pawlak, Mariusz; Janssen, Liesbeth M C; Moiseyev, Nimrod; van de Meerakker, Sebastiaan Y T; van der Avoird, Ad; Koch, Christiane P; Narevicius, Edvardas
2016-01-01
Anisotropy is a fundamental property of particle interactions. It occupies a central role in cold and ultra-cold molecular processes, where long range forces have been found to significantly depend on orientation in ultra-cold polar molecule collisions. Recent experiments have demonstrated the emergence of quantum phenomena such as scattering resonances in the cold collisions regime due to quantization of the intermolecular degrees of freedom. Although these states have been shown to be sensitive to interaction details, the effect of anisotropy on quantum resonances has eluded experimental observation so far. Here, we directly measure the anisotropy in atom-molecule interactions via quantum resonances by changing the quantum state of the internal molecular rotor. We observe that a quantum scattering resonance at a collision energy of $k_B$ x 270 mK appears in the Penning ionization of molecular hydrogen with metastable helium only if the molecule is rotationally excited. We use state of the art ab initio and ...
Resonance scattering at third-order exceptional points
We analyze scattering cross sections at and near third-order exceptional points (EP3), i.e., points in physical parameter space where three energies and eigenfunctions coincide. At an EP3, the Green’s function contains a pole of third order, in addition to poles of second and first order. We show that the interference of the three pole terms produces a rich variety of line shapes at the exceptional point and in its neighbourhood. This is demonstrated by extending previous work on two harmonic oscillators to a system of three driven coupled damped oscillators. We also discuss the similarities and the differences in the behaviour of the amplitudes in the classical problem and the scattering cross sections in the quantum mechanical problem at the EP3. (paper)
New Physics / Resonances in Vector Boson Scattering at the LHC
Reuter, J.; Kilian, W.; Ohl, T.; Sekulla, M.
2016-01-01
Vector boson scattering is (together with the production of multiple electroweak gauge bosons) the key process in the current run 2 of LHC to probe the microscopic nature of electroweak symmetry breaking. Deviations from the Standard Model are generically parameterized by higher-dimensional operators, however, there is a subtle issue of perturbative unitarity for such approaches for the process above. We discuss a parameter-free unitarization prescription to get physically meaningful predicti...
Study of giant resonances at high excitation energy by alpha inelastic scattering
Angular distributions of 340 and 480 MeV alpha particles inelastically scattered by 208Pb, 116Sn and 58Ni up to 60 MeV of excitation have been measured. The experimental inelastic spectra have been analysed by means of a new global method. The repartition of multipole strength shows the already known low energy giant resonances into more details. New high energy giant resonances are observed
Exploring the extended scalar sector with resonances in vector boson scattering
Khan, Najimuddin; Rakshit, Subhendu; Shaw, Avirup
2016-01-01
We show that the study of scalar resonances at various vector boson scattering processes at the Large Hadron Collider can serve as a useful tool to distinguish between different extensions of the scalar sector of the Standard Model. The recent measurement of the Higgs boson properties leaves enough room for the extended scalar sectors to be relevant for such studies. The shape of the resonances, being model dependent, can shed light on the viable parameter space of a number of theoretical models.
Hyper-Raman scattering and three-photon resonant ionization: Competitive effects
A semiclassical theory of hyper-Raman scattering and three-photon resonant ionization via the coupled density-matrix and Maxwell equations is presented. A simplified three-level atom model is obtained, which includes two-photon resonant pumping and time dependent photoionization rates. We consider conditions typically encountered in atomic vapours to simulate numerically pulse propagation. A strong depletion of the photoionization probability in the hyper-Raman field saturation regime is predicted. (author). 17 refs, 8 figs
Complementarity of resonant and nonresonant strong WW scattering at SSC and LHC
Signals and backgrounds for strong WW scattering at the SSC and LHC are considered. Complementarity of resonant signals in the I=1 WZ channel and nonresonant signals in the I=2W+W+ channel is illustrated using a chiral lagrangian with a J=1 ''ρ'' resonance. Results are presented for purely leptonic final states in the W±Z, W+W++W-W-, and ZZ channels
Experimental investigation of the 12C+12C fusion at very low energies by direct and indirect methods
The 12C+12C fusion reaction plays a crucial role during stellar evolution. The astrophysically important energy range spans from 1 MeV to 3 MeV. However, its cross section has not been determined with enough precision, despite numerous studies, due to the extremely low reaction cross sections and the large experimental background. To allow measurements of the 12C+12C fusion at astrophysical energies, we developed an efficient thick-target method using large-area silicon strip detectors. Further measurements at even lower energies will be performed using coincidences between a silicon-detector and a Ge-detector array, at the high-current accelerator under construction at the University of Notre Dame. Since the coincidence method does not allow obtaining information about the channels without gamma-ray emission, a solenoid spectrometer has been constructed for complementary measurements. Meanwhile, we are also investigating the 24Mg(α, α') reaction using the Grand Raiden Spectrometer at RCNP to search for potential resonances in the 12C+12C fusion reaction. Preliminary results from these measurements will be presented.
Electron-scattering form factors for the giant dipole resonance
Using a previously developed formalism based on the generator coordinate method, the longitudinal- and transverse-excitation form factors for the giant dipole resonance are obtained. Although microscopically established, that approach can provide analytic and compact expressions for some selected closed-shell nuclei. Our calculations are then compared with the phenomenological Goldhaber-Teller isospin-mode result and the experimental data. From our method, we derive restricted RPA-results (quadratic approximation) which are analysed. (author)
Resonances and analyticity of scattering wave function for square-well-type potentials
In this paper we extend our previous analysis of the scattering of wave packets in one dimension to the case of the square-well potential. The analytic properties of the general scattering solution are emphasized thereby making the analysis useful as introductory material for a more sophisticated S-matrix treatment. The square-well model is particularly interesting because of its application to the deuteron problem. Resonance scattering, barrier penetration, time delay, and line shape are discussed at the level of the first-year graduate student
Diffractometer for small angle resonant soft x-ray scattering under magnetic field
There has been a recent increasing interest in a topological spin texture, so-called skyrmion crystal, stimulated by small-angle neutron scattering and Lorentz-TEM studies. For the purpose of measuring the resonant soft x-ray magnetic scattering to characterize the distribution of magnetic moments with long-wavelength in range of a few tens to hundreds nm, we have developed a diffractometer for small angle soft x-ray scattering. The principle features of the diffractometer and the initial experimental results are presented.
Weier, C.; Adam, R.; Rudolf, D.; Frömter, R.; Grychtol, P.; Winkler, G.; Kobs, A.; Oepen, H. P.; Kapteyn, H. C.; Murnane, M. M.; Schneider, C. M.
2015-01-01
We characterize the magnetic domain structure of Co/Pt multilayer films on length scales below one hundred nanometers using resonant magnetic scattering and magnetic force microscopy. The extreme ultraviolet light for the scattering experiment is created by a laser-based high-order harmonic generation source. After illumination with intense ultrashort infrared laser pulses, we observe pronounced changes in the magnetic structure and morphology. This study points out the importance of a detailed analysis of the different laser-induced modifications of a magnetic thin film that influence the scattering patterns.
Valence neutrons' role in the collisions 13C+12C and 13C+13C
The resonant behaviour is not limited to collisions between α-like nuclei: resonance structures have been observed in the direct channels for the 13C+12C and 13C+13C collisions; in the contrary, the resonances observed in the fusion channels are not so pronounced as in the 12C+12C case: the valence neutrons increase the number of reaction channels and the density of states in the states in the compound nuclei, the resonances are therefore 'washed out' and it is difficult to observe them experimentally
Multiple scattering dynamics of fermions at an isolated p-wave resonance
Thomas, Ryan; Tiesinga, Eite; Wade, Andrew C J; Blakie, P Blair; Deb, Amita B; Kjærgaard, Niels
2016-01-01
The wavefunction for indistinguishable fermions is anti-symmetric under particle exchange, which directly leads to the Pauli exclusion principle, and hence underlies the structure of atoms and the properties of almost all materials. In the dynamics of collisions between two indistinguishable fermions this requirement strictly prohibits scattering into 90 degree angles. Here we experimentally investigate the collisions of ultracold clouds fermionic $\\rm^{40}K$ atoms by directly measuring scattering distributions. With increasing collision energy we identify the Wigner threshold for p-wave scattering with its tell-tale dumb-bell shape and no $90^\\circ$ yield. Above this threshold effects of multiple scattering become manifest as deviations from the underlying binary p-wave shape, adding particles either isotropically or axially. A shape resonance for $\\rm^{40}K$ facilitates the separate observation of these two processes. The isotropically enhanced multiple scattering mode is a generic p-wave threshold phenomen...
Measurements of the 6He+p resonant scattering
Measurements of the p(6He,p) elastic scattering excitation function have been performed in the RIBRAS system using a 6He secondary beam and a CH2 polyethylene thick target. The motivation is to observe states of the compound nucleus 7Li in the excitation energy range of Eexc7Li = 10.8-11.8MeV, where the isobaric analog state of 7He ground state lies. Excitation functions have been obtained at three laboratory angles θlab = 0°, 20°, and 25° which correspond to θc.m = 180°, 140°, and 130°
Resonances in coupled ?K, ?K scattering from lattice QCD
Wilson, David J.; Dudek, Jozef J.; Edwards, Robert G.; Thomas, Christopher E.
2015-01-01
Coupled-channel $\\pi K$ and $\\eta K$ scattering amplitudes are determined by studying the finite-volume energy spectra obtained from dynamical lattice QCD calculations. Using a large basis of interpolating operators, including both those resembling a $q\\bar{q}$ construction and those resembling a pair of mesons with relative momentum, a reliable excited-state spectrum can be obtained. Working at ${m_\\pi=391\\,\\mathrm{MeV}}$, we find a gradual increase in the $J^P=0^+$ $\\pi K$ phase-shift which...
High-sensitivity pesticide detection using particle-enhanced resonant Raman scattering
Ranjan, Bikas; Saito, Yuika; Verma, Prabhat
2016-03-01
The use of pesticides in agriculture has raised concerns, as even a small residual of pesticide on food can be harmful. It is therefore of great importance to develop a robust technique to detect tiny amounts of pesticides. Although Raman spectroscopy is frequently used for chemical identification, it is not suitable for extremely low molecular concentrations. We propose a technique called particle-enhanced resonant Raman spectroscopy to detect extremely low concentrations of pesticides, where gold nanoparticles of desired plasmonic resonance are synthesized to match the resonance in Raman scattering. We successfully demonstrated the detection of extremely low amounts of pesticides on oranges.
Efficient and robust analysis of complex scattering data under noise in microwave resonators
Superconducting microwave resonators are reliable circuits widely used for detection and as test devices for material research. A reliable determination of their external and internal quality factors is crucial for many modern applications, which either require fast measurements or operate in the single photon regime with small signal to noise ratios. Here, we use the circle fit technique with diameter correction and provide a step by step guide for implementing an algorithm for robust fitting and calibration of complex resonator scattering data in the presence of noise. The speedup and robustness of the analysis are achieved by employing an algebraic rather than an iterative fit technique for the resonance circle
Scattering phase shift for elastic two pion scattering and the rho resonance in lattice QCD
In this thesis we use lattice QCD to compute scattering phase shifts for elastic two-pion scattering in the isospin I=1 channel. Using Luescher's formalism, we derive the scattering phase shifts for different total momenta of the two-pion system in a non-rest frame. Furthermore we analyse the symmetries of the non-rest frame lattices and construct 2-pion and rho operators transforming in accordance with these symmetries. The data was collected for a 323 x 64 and a 403 x 64 lattice with Nf=2 clover improved Wilson fermions at a pion mass around 290 MeV and a lattice spacing of about 0.072 fm.
Scattering phase shift for elastic two pion scattering and the rho resonance in lattice QCD
Gutzwiller, Simone
2012-10-08
In this thesis we use lattice QCD to compute scattering phase shifts for elastic two-pion scattering in the isospin I=1 channel. Using Luescher's formalism, we derive the scattering phase shifts for different total momenta of the two-pion system in a non-rest frame. Furthermore we analyse the symmetries of the non-rest frame lattices and construct 2-pion and rho operators transforming in accordance with these symmetries. The data was collected for a 32{sup 3} x 64 and a 40{sup 3} x 64 lattice with N{sub f}=2 clover improved Wilson fermions at a pion mass around 290 MeV and a lattice spacing of about 0.072 fm.
无
2011-01-01
The proton resonant properties in 18Ne, which determine the reaction rate of the key stellar 14O(α,p)17F reaction, have been studied by using a technique of proton resonant elastic scattering of 17F+p. A 4.22 MeV/nucleon 17F radioactive ion (RI) beam was produced via a projectile-fragmentation reaction, and separated by a Radioactive Ion Beam Line in Lanzhou (RIBLL). By bombarding a thick (CH2)n target, the energy spectra of the recoiled protons were measured by two ΔE-E silicon telescopes at the center-of-mass scattering angles of θc.m.≈175°±5°, θc.m.≈152°±8°, respectively. Several proton resonances in 18Ne were ob served clearly. A further R-matrix analysis of the experimental data is under way to determine the resonant parameters. The present work reports the preliminary results briefly.
X-ray resonant scattering study of the quadrupolar order in UPd_{3}
McMorrow, D.F.; McEwen, K.A.; Steigenberger, U.;
2001-01-01
Quadrupolar ordering in a 5f electron system has been observed directly for the first time, using x-ray scattering techniques. In UPd(3) at low temperatures satellite peaks appear at (1, 0, l) (orthorhombic notation) with I odd and even. Both sets of peaks show a resonant enhancement of the scatt...
Relativistic description of πd elastic scattering in the (3,3) resonance region
The πd elastic scattering observables are calculated in the energy range 142 to 256 MeV using a relativistic three-body theory. The non-resonant πN partial waves are included perturbatively. Various sets of tensor forces are elaborated. The sensitivity to the description of the NN and πN channels is investigated
Resonant Rayleigh scattering of exciton-polaritons in multiple quantum wells
Malpuech, Guillaume; Kavokin, Alexey; Langbein, Wolfgang Werner;
2000-01-01
A theoretical concept of resonant Rayleigh scattering (RRS) of exciton-polaritons in multiple quantum wells (QWs) is presented. The optical coupling between excitons in different QWs can strongly affect the RRS dynamics, giving rise to characteristic temporal oscillations on a picosecond scale. B...
Resonant Scattering off Magnetic Impurities in Graphene: Mechanism for Ultrafast Spin Relaxation
Kochan, D.; Gmitra, M.; Fabian, J.
We give a tutorial account of our recently proposed mechanism for spin relaxation based on spin-flip resonant scattering off local magnetic moments. The mechanism is rather general, working in any material with a resonant local moment, but we believe that its particular niche is graphene, whose measured spin relaxation time is 100-1000 ps. Conventional spin-orbit coupling based mechanisms (Elliott-Yafet or Dyakonov-Perel) would require large concentrations (1000 ppm) of impurities to explain this. Our mechanism needs only 1 ppm of resonant local moments, as these act as local spin hot spots: the resonant scatterers do not appear to substantially affect graphene's measured resistivity, but are dominating spin relaxation. In principle, the local moments can come from a variety of sources. Most likely would be organic molecule adsorbants or metallic adatoms. As the representative model, particularly suited for a tutorial, we consider hydrogen adatoms which are theoretically and experimentally demonstrated to yield local magnetic moments when chemisorbed on graphene. We introduce the scattering formalism and apply it to graphene, to obtain the T-matrix and spin-flip scattering rates using the generalized Fermi golden rule.
Lamb, D. Q.; Wang, J. C. L.; Wasserman, I.
1992-01-01
We explain the relative line strengths in gamma-ray bursts in terms of cyclotron resonant scattering. We describe the line signature of neutron star rotation and discuss the possibility that variations seen in the strengths and widths of the lines in GB780325 and GB870303 are due to rotation.
On the Possibility of Resonances in Longitudinally Polarized Vector Boson Scattering
Veltman, M.J.G.; Veltman, H.
1991-01-01
Assuming that no Higgs has been found below 1 TeV, we study the physics of longitudinally polarized vector boson ( ) scattering in the TeV region, using a one loop calculation and partial wave analysis. We show that the occurrence of a resonance in the isospin I = 1 channel depends on a certain para
Asymptotics for a resonance-counting function for potential scattering on cylinders
Christiansen, T.
2003-01-01
We study certain resonance-counting functions for potential scattering on infinite cylinders or half-cylinders. Under certain conditions on the potential, we obtain asymptotics of the counting functions, with an explicit formula for the constant appearing in the leading term.
Byelobrov, V.; Benson, T. M.; Čtyroký, Jiří; Sauleau, R.; Nosich, A. I.
New York : IEEE, 2010 - (Jaworski, M.; Marciniak, M.), s. 5548981 ISBN 978-1-4244-7799-9. [12th International Conference on Transparent Optical Networks (ICTON), 2010. Mnichov (DE), 27.06.2010-01.07.2010] Institutional research plan: CEZ:AV0Z20670512 Keywords : Plasmon resonances * Scattering * Silver grating Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Nuclear resonant scattering of Synchrotron radiation from nuclei in the Browninan motion
Razdan, Ashok
2001-01-01
The time evolution of the coherent forward scattering of Synchrotron radiation for resonant nuclei in Brownian motion is studied . Apart from target thickness, the appearance of dynamical beats also depends on $\\alpha$ which is the ratio of harmonic force constant to the damping force constant of a harmonic oscillator undergoing Brownian motion.
Effective theory calculation of resonant high-energy scattering
Beneke, Martin; Signer, A; Zanderighi, G
2004-01-01
Tests of the standard model and its hypothetical extensions require precise theoretical predictions for processes involving massive, unstable particles. It is well-known that ordinary weak-coupling perturbation theory breaks down due to intermediate singular propagators. Various pragmatic approaches have been developed to deal with this difficulty. In this paper we construct an effective field theory for resonant processes utilizing the hierarchy of scales between the mass of the unstable particle, M, and its width, Gamma. The effective theory allows calculations to be systematically arranged into a series in g^2 and Gamma/M, and preserves gauge invariance in every step. We demonstrate the applicability of this method by calculating explicitly the inclusive line shape of a scalar resonance in an abelian gauge-Yukawa model at next-to-leading order in Gamma/M and the weak couplings. We also discuss the extension to next-to-next-to-leading order and compute an interesting subset of these corrections.
Observations of resonance-like structures for positron-atom scattering at intermediate energies
Absolute values of elastic differential cross sections (DCS's) are measured for position (e+) scattering by argon (8.7-300 eV) krypton (6.7-400 eV) and also neon (13.6-400 eV) using a crossed-beam experimental setup. When the DCS's are plotted at fixed scattering angles of 30 degrees, 60 degrees, 90 degrees and 120 degrees versus energy it has been found that well-defined resonance-like structures are found at an energy of 55-60 eV for argon and at 25 and 200 eV for krypton, with a broader structure found between 100-200 eV for neon. These observed resonance-like structures are unusual because they occur at energies well above the known inelastic thresholds for these atoms. They may represent examples of open-quotes coupled channel shape resonancesclose quotes, first predicted by Higgins and Burke [1] for e+-H scattering in the vicinity of 36 eV (width ∼ 4 eV), which occurs only when both the elastic and positronium formation scattering channels are considered together. A more recent e+-H calculation by Hewitt et al. [2] supports the Higgins and Burke prediction. These predictions and the present observations suggest the existence of a new type of atomic scattering resonance
KsKs resonances in deep inelastic scattering at HERA
Barbi, M; collaboration, for the ZEUS
2003-01-01
Inclusive KsKs production in deep inelastic ep scattering at HERA has been studied with the ZEUS detector using an integrated luminosity of 120 pb-1. Two states are observed at masses of 1537{+9}{-8} MeV and 1726{+-7} MeV, as well as an enhancement around 1300 MeV. The state at 1537 MeV is consistent with the well established f'2(1525). The state at 1726 MeV may be the glueball candidate f0(1710). However, it's width of 38{+20}{-14} MeV is narrower than 125{+-10} MeV observed by previous expe...
KsKs resonances in deep inelastic scattering at HERA
Barbi, M
2003-01-01
Inclusive KsKs production in deep inelastic ep scattering at HERA has been studied with the ZEUS detector using an integrated luminosity of 120 pb-1. Two states are observed at masses of 1537{+9}{-8} MeV and 1726{+-7} MeV, as well as an enhancement around 1300 MeV. The state at 1537 MeV is consistent with the well established f'2(1525). The state at 1726 MeV may be the glueball candidate f0(1710). However, it's width of 38{+20}{-14} MeV is narrower than 125{+-10} MeV observed by previous experiments for the f0(1710).
Fermi-edge singularity in the vicinity of the resonant scattering condition.
Mkhitaryan, V V; Raikh, M E
2011-05-13
Fermi-edge absorption theory predicting the spectrum A(ω) ∝ ω(-2δ(0)/π+δ(0)92)/π2) relies on the assumption that scattering phase δ(0) is frequency independent. The dependence of δ(0) on ω becomes crucial near the resonant condition, where the phase changes abruptly by π. In this limit, because of the finite time spent by electron on a resonant level, the scattering is dynamic. We incorporate the finite time delay into the theory, solve the Dyson equation with a modified kernel, and find that, near the resonance, A(ω) behaves as ω(-3/4)|lnω|. Scattering off the core hole becomes resonant in 1D and 2D in the presence of an empty subband above the Fermi level; then a deep hole splits off a level from the bottom of this subband. Fermi-edge absorption in the regime when resonant level transforms into a Kondo peak is discussed. PMID:21668193
Potential effect of resonant scattering from multiple swimbladders on audition in juvenile fish
Hastings, Mardi C.
2003-04-01
The swimbladder, a gas-filled chamber in the abdominal cavity of most bony fishes, is a hydrostatic organ that enables fish to maintain neutral buoyancy; however, it also responds to acoustic pressure and radiates a secondary acoustic field that enhances detection capability of the inner ear. Recent experiments have indicated that resonant response of the swimbladder may control the auditory bandwidth in at least four species of fish [Hastings et al., J. Acoust. Soc. Am. 110, 2640 (2001)]. The auditory bandwidths of these fishes, however, do not change appreciably while they grow even though the resonance frequency of the swimbladder decreases with increasing body length. Results of an analysis inspired by Feiullade et al. [J. Acoust. Soc. Am. 112, 2206 (2002)] show that the downward shift and broadening associated with resonance of the aggregate scattered field from multiple fish is perhaps sufficient enough to account for this discrepancy. Effects of resonant characteristics of a single swimbladder, fish length, and number of fish on the changes in the collective scattered field are presented. Thus the resonant scattered field created by relatively large schools of juvenile fish may enhance their auditory capability.
Advances in gamma ray resonant scattering and absorption long-lived isomeric nuclear states
Davydov, Andrey V
2015-01-01
This book presents the basics and advanced topics of research of gamma ray physics. It describes measuring of Fermi surfaces with gamma resonance spectroscopy and the theory of angular distributions of resonantly scattered gamma rays. The dependence of excited-nuclei average lifetime on the shape of the exciting-radiation spectrum and electron binding energies in the spectra of scattered gamma rays is described. Resonant excitation by gamma rays of nuclear isomeric states with long lifetime leads to the emission and absorption lines. In the book, a new gamma spectroscopic method, gravitational gamma spectrometry, is developed. It has a resolution hundred million times higher than the usual Mössbauer spectrometer. Another important topic of this book is resonant scattering of annihilation quanta by nuclei with excited states in connection with positron annihilation. The application of the methods described is to explain the phenomenon of Coulomb fragmentation of gamma-source molecules and resonant scatt...
Raman scattering enhancement in photon-plasmon resonance mediated metal-dielectric microcavity
Here, we report the photon-plasmon interaction scheme and enhanced field strengths resulted into the amplification of phonon in a novel microcavity. A metal-dielectric microcavity, with unified cavity photonic mode and localized surface plasmon resonances, is visualized by impregnating the gold nanoparticles into the deep see-through nano-sized pores of porous silicon microcavity. The intense optical field strengths resulting from the photon-plasmon interactions are probed by both resonant and non-resonant Raman scattering experiments. Due to photon-plasmon-phonon interaction mechanism, several orders of enhancement in the intensity of scattered Raman Stokes photon (at 500 cm−1) are observed. Our metal nanoparticle-microcavity hybrid system shows the potential to improve the sensing figure of merit as well as the applications of plasmonics for optoelectronics, photovoltaics, and related technologies
Resonant scattering of X-ray emission lines in the hot intergalactic medium
Churazov, E; Sazonov, S; Sunyaev, R
2010-01-01
While very often a hot intergalactic medium (IGM) is optically thin to continuum radiation, the optical depth in resonant lines can be of order unity or larger. Resonant scattering in the brightest X-ray emission lines can cause distortions in the surface brightness distribution, spurious variations in the abundance of heavy elements, changes in line spectral shapes and even polarization of line emission. The magnitude of these effects not only depends on the density, temperature and ionization state of the gas, but is also sensitive to the characteristics of the gas velocity field. This opens a possibility to use resonant scattering as a convenient and powerful tool to study IGM properties. We discuss the application of these effects to galaxy clusters.
Resonant stimulation of Raman scattering from single-crystal thiophene/phenylene co-oligomers
Amplified Raman scattering was observed from single crystals of thiophene/phenylene co-oligomers (TPCOs). Under ns-pulsed excitation, the TPCO crystals exhibited amplified spontaneous emission (ASE) at resonant absorption wavelengths. With increasing excitation wavelength to the 0-0 absorption edge, the stimulated resonant Raman peaks appeared both in the 0-1 and 0-2 ASE band regions. When the excitation wavelength coincided with the 0-1 ASE band energy, the Raman peaks selectively appeared in the 0-2 ASE band. Such unusual enhancement of the 0-2 Raman scattering was ascribed to resonant stimulation via vibronic coupling with electronic transitions in the uniaxially oriented TPCO molecules
Raman scattering enhancement in photon-plasmon resonance mediated metal-dielectric microcavity
Guddala, Sriram; Narayana Rao, D., E-mail: dnr.laserlab@gmail.com, E-mail: dnrsp@uohyd.ernet.in [School of Physics, University of Hyderabad, Hyderabad 500 046 (India); Dwivedi, Vindesh K.; Vijaya Prakash, G. [Nanophotonics Laboratory, Department of Physics, IIT Delhi, New Delhi 110 016 (India)
2013-12-14
Here, we report the photon-plasmon interaction scheme and enhanced field strengths resulted into the amplification of phonon in a novel microcavity. A metal-dielectric microcavity, with unified cavity photonic mode and localized surface plasmon resonances, is visualized by impregnating the gold nanoparticles into the deep see-through nano-sized pores of porous silicon microcavity. The intense optical field strengths resulting from the photon-plasmon interactions are probed by both resonant and non-resonant Raman scattering experiments. Due to photon-plasmon-phonon interaction mechanism, several orders of enhancement in the intensity of scattered Raman Stokes photon (at 500 cm{sup −1}) are observed. Our metal nanoparticle-microcavity hybrid system shows the potential to improve the sensing figure of merit as well as the applications of plasmonics for optoelectronics, photovoltaics, and related technologies.
Optically resonant magneto-electric cubic nanoantennas for ultra-directional light scattering
Sikdar, Debabrata, E-mail: debabrata.sikdar@monash.edu; Premaratne, Malin [Advanced Computing and Simulation Laboratory (A chi L), Department of Electrical and Computer Systems Engineering, Monash University, Clayton 3800, Victoria (Australia); Cheng, Wenlong [Department of Chemical Engineering, Faculty of Engineering, Monash University, Clayton 3800, Victoria (Australia); The Melbourne Centre for Nanofabrication, 151 Wellington Road, Clayton 3168, Victoria (Australia)
2015-02-28
Cubic dielectric nanoparticles are promising candidates for futuristic low-loss, ultra-compact, nanophotonic applications owing to their larger optical coefficients, greater packing density, and relative ease of fabrication as compared to spherical nanoparticles; besides possessing negligible heating at nanoscale in contrast to their metallic counterparts. Here, we present the first theoretical demonstration of azimuthally symmetric, ultra-directional Kerker's-type scattering of simple dielectric nanocubes in visible and near-infrared regions via simultaneous excitation and interference of optically induced electric- and magnetic-resonances up to quadrupolar modes. Unidirectional forward-scattering by individual nanocubes is observed at the first generalized-Kerker's condition for backward-scattering suppression, having equal electric- and magnetic-dipolar responses. Both directionality and magnitude of these unidirectional-scattering patterns get enhanced where matching electric- and magnetic-quadrupolar responses spectrally overlap. While preserving azimuthal-symmetry and backscattering suppression, a nanocube homodimer provides further directionality improvement for increasing interparticle gap, but with reduced main-lobe magnitude due to emergence of side-scattering lobes from diffraction-grating effect. We thoroughly investigate the influence of interparticle gap on scattering patterns and propose optimal range of gap for minimizing side-scattering lobes. Besides suppressing undesired side-lobes, significant enhancement in scattering magnitude and directionality is attained with increasing number of nanocubes forming a linear chain. Optimal directionality, i.e., the narrowest main-scattering lobe, is found at the wavelength of interfering quadrupolar resonances; whereas the largest main-lobe magnitude is observed at the wavelength satisfying the first Kerker's condition. These unique optical properties of dielectric nanocubes thus can
Mayer, M., E-mail: Matej.Mayer@ipp.mpg.de [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)
2012-08-15
A statistical analysis of experimental and theoretical SigmaCalc 1.6 data for the {sup 12}C({sup 4}He, {sup 4}He){sup 12}C cross-section was performed in the energy range 1600-8200 keV at backscattering angles in the range 149-172 Degree-Sign . In the vicinity of sharp resonances experimental data show a very large scatter, in energy ranges with sufficiently smooth cross-section the overall uncertainty of a single measured cross-section data set is 10.3%. SigmaCalc allows averaging of experimental data at different angles, resulting in an averaged experimental cross-section with an accuracy of 2.1-6.6%. While SigmaCalc-2000 showed some systematic deviations from the experimental data, the improved SigmaCalc-2012 shows agreement with the average experimental cross-section within its error bars over most of the energy range. SigmaCalc and the average cross-section were compared to benchmark measurements at 2000-6000 keV. The deviations between SigmaCalc-2000 and experimental data were confirmed in the benchmark. Both SigmaCalc-2012 and the average cross-section agree with the benchmark over almost the whole energy range.
Flux-averaged and flux-integrated cross sections for quasi-elastic neutrino charged-current scattering on nuclei are analyzed. It is shown that the flux-integrated differential cross sections are less dependent on nuclear models than the flux-averaged ones. We calculate these cross sections using the relativistic distorted-wave impulse approximation and relativistic Fermi gas model with the Booster Neutrino Beamline flux and compare the results with the recent MiniBooNE experimental data. Within these models an axial mass MA is extracted from a fit of the measured dσ/dQ2 cross section. The extracted value of MA=1.37±0.05 GeV/c2 is consistent with the MiniBooNE result. While the measured and calculated double differential cross sections dσ/dTdcosθ generally agree, the Fermi gas model predictions are typically lower than data at low muon energies and scattering angles.
Sub-coulombian fusion of 12 C + 12 C measured with the γ rays improved technique
In this work we report the measurements carried out in the National Institute of Nuclear Research of Mexico (ININ) for the absolute section of fusion of the system 12 C + 12 C in an interval of energy of Ec.m. 4.5-6.5 MeV with fine steps of 75 keV. The objective of measuring in fine steps is to register all the existent resonances. To be able to obtain an absolute normalization of the cross section, it was applied a method that allows to measure simultaneously the one number of projectiles that arrive to the target, as well as the numbers of nuclei in the target, even when this doesn't stay constant. In the chapter 2 the experimental procedure it is described, it is carried out with detail the analysis of the data and the results are shown. Later on the chapter 3 it is described with detail the method used for the absolute normalization, that is to say the form of obtaining the quantities Np and ηT of the equation is explained and the obtained results are presented. Additionally in the chapter 4 it was carried out a theoretical analysis applying models as that of barrier penetration and the optical model combined with the Breit-Wigner theory with the purpose of being able to reproduce the resonances of the excitation function. In the chapter 5 the concept of S-Astrophysicist factor it is introduced and this value is calculated for our data. Finally in the chapter 6 the conclusions of this work are presented. (Author)
Inelastic scattering of 84 MeV/u 170 projectiles have been used to excite the giant resonances (GR) in various nuclei ranging from A=60 to A=232. For the isoscalar giant quadrupole resonance (ISGQR), the energy and width of the resonance, as well as the EWSR obtained from the measured cross sections, are in agreement with the known systematics for A>40. The observed GMR strengths are close to 100% EWRS and are consistent with other recent experimental results using heavy ion projectiles. These results lead to a somewhat different picture than that provided by previous studies using light projectiles. Strength is also observed at high excitation energy. The analysis of these resonances is in progress. Our study of the fission decay of GR in 232 Th leads to a somewhat different conclusion than previously deduced from data obtained with light ion projectiles, where no evidence for the fission decay of the ISGQR has been found. In the present work, due to the very good peak-to-continuum ratio, a structure is observed in the fission coincidence spectrum around 10 MeV which can be attributed to the fission decay of giant resonances. The measured fission probability is consistent with a statistical decay of the ISGQR. 10 figs
A Model of Resonance Scattering on Curved Quantum Wires
Exner, Pavel
A model of electron motion in a curved quantum wire of a finite length 2D attached to a pair of macroscopic electrodes is studied. Regarding the problem as a two-dimensional one, we model the electrodes as halfplanes and the quantum wire as a line segment joining them; it supports a potential which is a combination of a constant transversal-mode energy and an attractive curvature-induced term. We show that the bound states which may be present at an infinite quantum wire turn into resonances and that spectral concentration is valid as D .Translated AbstractEin Modell der Resonanzstreuung auf gekrümmten, dünnen DrähtenDas Modell einer Elektronenbewegung in einem gekrümmten, ultradünnen Draht der Länge 2D, der zwei makroskopische Elektroden verbindet, wird untersucht. Das Modell als zweidimensional betrachtend, nehmen wir die Elektroden als Halbebenen und den Draht als verbindendes Liniensegment. Das Potential ist eine Kombination aus konstanter Transversalmoden-energie und einem anziehenden, von der Krümmung hervorgerufenen Term. Wir zeigen, daß der gebundene Zustand, der im unendlich langen Draht auftreten kann, in Resonanzen übergeht, und die Spektraldichte für D gilt.
Development of a graphite polarization analyzer for resonant inelastic x-ray scattering.
Gao, Xuan; Burns, Clement; Casa, Diego; Upton, Mary; Gog, Thomas; Kim, Jungho; Li, Chengyang
2011-11-01
Resonant inelastic x-ray scattering (RIXS) is a powerful technique for studying electronic excitations in correlated electron systems. Current RIXS spectrometers measure the changes in energy and momentum of the photons scattered by the sample. A powerful extension of the RIXS technique is the measurement of the polarization state of the scattered photons which contains information about the symmetry of the excitations. This long-desired addition has been elusive because of significant technical challenges. This paper reports the development of a new diffraction-based polarization analyzer which discriminates between linear polarization components of the scattered photons. The double concave surface of the polarization analyzer was designed as a good compromise between energy resolution and throughput. Such a device was fabricated using highly oriented pyrolytic graphite for measurements at the Cu K-edge incident energy. Preliminary measurements on a CuGeO(3) sample are presented. PMID:22128967
Low-energy $DD^{*+}$ Scattering and the Resonance-like Structure $Z_c(3900)$
Chen, Ying; Lei, Yu-Hong; Li, Ning; Liang, Jian; Liu, Chuan; Liu, Hang; Liu, Jin-Long; Liu, Liuming; Liu, Yong-Fu; Liu, Yu-Bin; Liu, Zhaofeng; Ma, Jian-Ping; Wang, Zhan-Lin; Yang, Yi-Bo; Zhang, Jian-Bo
2014-01-01
In this exploratory lattice study, low-energy scattering of $D$ and $D^*$ meson are analyzed using lattice QCD with $N_f=2$ twisted mass fermion configurations with three pion mass values. The calculation is performed within single-channel L\\"uscher's finite-size formalism. The threshold scattering parameters, namely the scattering length $a_0$ and the effective range $r_0$, for the $s$-wave scattering in $J^P=1^+$ channel are extracted. For the cases in our study, the interaction between the two charmed mesons is weakly repulsive. Our lattice results therefore do not support the possibility of a shallow bound state for the two charmed mesons for the pion mass values we studied. This calculation provides some useful information on the nature of the newly discovered resonance-like structure $Z_c(3900)$ by various experimental groups.
Directional Fano Resonances at Light Scattering by a High Refractive Index Dielectric Sphere
Tribelsky, Michael I; Litman, Amelie; Eyraud, Christelle; Moreno, Fernando
2016-01-01
In this research, we report the experimental evidence of the directional Fano resonances at the scattering of a plane, linearly polarized electromagnetic wave by a homogeneous dielectric sphere with high refractive index and low losses. We observe a typical asymmetric Fano profile for the intensity scattered in, practically, any given direction, while the overall extinction cross section remains Lorentzian. The phenomenon is originated in the interference of the selectively excited electric dipolar and quadrupolar modes. The selectivity of the excitation is achieved by the proper choice of the frequency of the incident wave. Thanks to the scaling invariance of the Maxwell equations, in these experiments we mimic the scattering of the visible and near IR radiation by a nanoparticle made of common superconductor materials (Si, Ge, GaAs, GaP) by the equivalent scattering of a spherical particle of 18 mm in diameter in the microwave range. The theory developed to explain the experiments extends the conventional F...
Itoh, Tamitake; Yamamoto, Yuko S.; Tamaru, Hiroharu; Biju, Vasudevanpillai; Wakida, Shin-ichi; Ozaki, Yukihiro
2014-05-01
We investigate electromagnetic coupling between plasmonic and molecular electronic resonances using single-molecular surface-enhanced resonance Raman scattering (SERRS) from single silver nanoparticle dimers. When dimers exhibit SERRS activity, their elastic light scattering spectra show two lines, which are temporally closing toward each other. The higher energy line eventually disappears at the time of SERRS quenching. A coupled-oscillator model composed of plasmonic and molecular electronic resonances consistently reproduces the above interesting results by decreasing coupling energy, indicating that SERRS can be a quantitative probe for strong coupling between the two resonances.
Acoustic resonance scattering from a multilayered cylindrical shell with imperfect bonding.
Rajabi, M; Hasheminejad, Seyyed M
2009-12-01
The method of wave function expansion is adopted to study the three dimensional scattering of a time-harmonic plane progressive sound field obliquely incident upon a multi-layered hollow cylinder with interlaminar bonding imperfection. For the generality of solution, each layer is assumed to be cylindrically orthotropic. An approximate laminate model in the context of the modal state equations with variable coefficients along with the classical T-matrix solution technique is set up for each layer to solve for the unknown modal scattering and transmission coefficients. A linear spring model is used to describe the interlaminar adhesive bonding whose effects are incorporated into the global transfer matrix by introduction of proper interfacial transfer matrices. Following the classic acoustic resonance scattering theory (RST), the scattered field and response to surface waves are determined by constructing the partial waves and obtaining the non-resonance (backgrounds) and resonance components. The solution is first used to investigate the effect of interlayer imperfection of an air-filled and water submerged bilaminate aluminium cylindrical shell on the resonances associated with various modes of wave propagation (i.e., symmetric/asymmetric Lamb waves, fluid-borne A-type waves, Rayleigh and Whispering Gallery waves) appearing in the backscattered spectrum, according to their polarization and state of stress. An illustrative numerical example is also given for a multi-layered (five-layered) cylindrical shell for which the stiffness of the adhesive interlayers is artificially varied. The sensitivity of resonance frequencies associated with higher mode numbers to the stiffness coefficients is demonstrated to be a good measure of the bonding strength. Limiting cases are considered and fair agreements with solutions available in the literature are established. PMID:19586650
Δ33 resonance in pion nucleus elastic, single, and double charge exchange scattering
The Δ33 resonance is strongly excited in pion-nucleon scattering, but there is clearly only a limited amount of information that can be learned in scattering the pion from an isolated nucleon. One learns that there is a resonance of mass 1232 MeV, width 115 MeV, and, if one is willing to introduce a dynamical model, something about the off-shell extension of the amplitude. One stands to learn much more from pion-nucleus scattering because in this case the Δ33 resonance has an opportunity to scatter from nucleons, and how this occurs is not well understood. What do we know about the Δ-N interaction for pion-nucleus scattering. The isobar-hole model was invented to deal directly with the Δ33-nucleus dynamics, and a phenomenological determination of the isobar shell-model potential was attempted. The unknown dynamics deltaU/sub Δ/ is contained in a central isoscalar spreading potential of strength W0 and a spin orbit potential deltaU0 = W0rho + spin-orbit. The real part of W0rho is measured relative to the nucleon-nucleus potential. From a more theoretical point of view, one would like to be able to calculate deltaU/sub Δ/, including its isospin dependence, from an underlying dynamical model which is formulated in terms of the basic effective meson-baryon couplings. Some salient properties of these couplings can be determined from models of quark-bag structure, which raises the exciting possibility of learning about these fundamental issues from pion scattering. Attempts at Los Alamos to build a theoretical framework to deal with these and other issues are described
Resonant X-ray scattering studies of concentrated aqueous solutions
The microscopic structure of concentrated aqueous electrolyte solutions has been studied by resonant X-ray diffraction (RXD). This technique provides a method for the measurement of the structure around a specific atom or ion in solution. In that sense, RXD is the X-ray equivalent of neutron diffraction with isotopic substitution (NDIS). The use of RXD as an alternative to NDIS has been considered of interest for some time; it is potentially one of the best methods for overcoming the most important limitation of the neutron diffraction technique, i.e. the lack of suitable isotopes for every atomic species. Third generation synchrotron sources offer an unprecedented opportunity for the further development of RXD to study the microscopic structure of liquids and amorphous materials. One of the main aims of this thesis was to check whether it could be possible to obtain results of comparable accuracy to those of NDIS. In this work, the hydration structures of Br-, Rb+, Sr2+ and Y3+ in concentrated aqueous solutions have been studied by RXD. A detailed account of how the experiments were carried out and the data analysis procedure is given. The results are compared with those obtained for the same ion by other techniques and to those obtained for similar systems by NDIS. The reliability of these results and the observed trends in the measured structure when compared to other ions in the same series are discussed. A comparative study of the structure of the three cations is also presented in this thesis. This work illustrates one of the main advantages of RXD: the possibility of carrying out systematic structural studies on all elements with atomic number greater than 28 (Ni). Finally, a critical discussion on the actual stage of development of RXD is presented. The results shown offer evidence of the future prospects of the technique and justify further efforts to develop it to the level of reliability and ease of use that NDIS has reached after more than three decades
Asano, Motoki; Özdemir, Şahin Kaya; Ikuta, Rikizo; Yang, Lan; Imoto, Nobuyuki; Yamamoto, Takashi
2016-01-01
We report the first observation of stimulated Brillouin scattering (SBS) with Brillouin lasing, and Brillouin-coupled four-wave-mixing (FWM) in an ultra-high-Q silica microbottle resonator. The Brillouin lasing was observed at the frequency of $\\Omega_B=2\\pi\\times10.4$ GHz with a threshold power of $0.45$ mW. Coupling between Brillouin and FWM was observed in both backward and forward scattering directions with separations of $2\\Omega_B$. At a pump power of $10$ mW, FWM spacing reached to 7th and 9th order anti-Stokes and Stokes, respectively.
de Lasson, Jakob Rosenkrantz; Kristensen, Philip Trøst; Mørk, Jesper
2012-01-01
We present a multiple-scattering formalism for simulating scattering of electromagnetic waves on spherical inhomogeneities in 3D. The formalism is based on the Lippmann-Schwinger equation and the electromagnetic Green's tensor and applies an expansion of the electric field on spherical wavefuncti...... wavefunctions. As an example, we analyze localized surface plasmons in chains of Ag spheres, and show how the resonances of such systems depend sensitively on the polarization of the incoming field, the spacing between the particles and the number of particles in the chain....
RBS and resonant scattering analysis of thin oxidic films prepared by sputtering
The oxygen content in various oxidic thin films has been determined from alpha scattering spectra based upon gauging with a rutile and a SrTiO3 crystal. Both RBS and scattering with the 3.04 MeV resonance (for O) were applied and compared to each other. Main findings are: - Gradient in O-content of TiO2 prepared by reactive magnetron sputtering at 300 C at various oxygen partial pressures. - Oxygen surplus in ITO films prepared by rf-diode sputtering. Variation in the oxygen content of nominal Cr2MnO4 prepared by magnetron sputtering at 350 C to 650 C.
Braicovich, L., E-mail: lucio.braicovich@polimi.it; Minola, M.; Dellea, G.; Ghiringhelli, G. [CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo Da Vinci 32, Milano I-20133 (Italy); Le Tacon, M. [Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Moretti Sala, M.; Morawe, C.; Peffen, J.-Ch.; Yakhou, F.; Brookes, N. B. [European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble F-38043 (France); Supruangnet, R. [Synchrotron Light Research Institute, Nakhon Ratchasima (Thailand)
2014-11-15
Resonant Inelastic X-ray Scattering (RIXS) in the soft x-ray range is an element-specific energy-loss spectroscopy used to probe the electronic and magnetic excitations in strongly correlated solids. In the recent years, RIXS has been progressing very quickly in terms of energy resolution and understanding of the experimental results, but the interpretation of spectra could further improve, sometimes decisively, from a full knowledge of the polarization of incident and scattered photons. Here we present the first implementation, in a high resolution soft-RIXS spectrometer used to analyze the scattered radiation, of a device allowing the measurement of the degree of linear polarization. The system, based on a graded W/B{sub 4}C multilayer mirror installed in proximity of the CCD detector, has been installed on the AXES spectrometer at the ESRF (European Synchrotron Radiation Facility); it has been fully characterized and it has been used for a demonstration experiment at the Cu L{sub 3} edge on a high-T{sub c} superconducting cuprate. The loss in efficiency suffered by the spectrometer equipped with this test facility was a factor 17.5. We propose also a more advanced version, suitable for a routine use on the next generation of RIXS spectrometers and with an overall efficiency up to 10%.
Ferrari, Eugenio; Spezzani, Carlo; Fortuna, Franck; Delaunay, Renaud; Vidal, Franck; Nikolov, Ivaylo; Cinquegrana, Paolo; Diviacco, Bruno; Gauthier, David; Penco, Giuseppe; Ribič, Primož Rebernik; Roussel, Eleonore; Trovò, Marco; Moussy, Jean-Baptiste; Pincelli, Tommaso; Lounis, Lounès; Manfredda, Michele; Pedersoli, Emanuele; Capotondi, Flavio; Svetina, Cristian; Mahne, Nicola; Zangrando, Marco; Raimondi, Lorenzo; Demidovich, Alexander; Giannessi, Luca; De Ninno, Giovanni; Danailov, Miltcho Boyanov; Allaria, Enrico; Sacchi, Maurizio
2016-01-01
The advent of free-electron laser (FEL) sources delivering two synchronized pulses of different wavelengths (or colours) has made available a whole range of novel pump–probe experiments. This communication describes a major step forward using a new configuration of the FERMI FEL-seeded source to deliver two pulses with different wavelengths, each tunable independently over a broad spectral range with adjustable time delay. The FEL scheme makes use of two seed laser beams of different wavelengths and of a split radiator section to generate two extreme ultraviolet pulses from distinct portions of the same electron bunch. The tunability range of this new two-colour source meets the requirements of double-resonant FEL pump/FEL probe time-resolved studies. We demonstrate its performance in a proof-of-principle magnetic scattering experiment in Fe–Ni compounds, by tuning the FEL wavelengths to the Fe and Ni 3p resonances. PMID:26757813
Bakker, E J; Lambert, Eric J. Bakker & David L.
1998-01-01
We have made the first detection of circumstellar absorption lines of the 12C13C (Phillips) system 1-0 band and the 12C16O first-overtone 2-0 band in the spectrum of the post-AGB star HD56126 (IRAS07134+1005). The rotational temperatures are lower for molecules with a higher permanent dipole moment. Derived relative column densities ratios are 12C12C/12C13C=36+-13, 12C16O/(12C12C+12C13C)=606+-230, and 12C16O/(12C14N+13C14N)=475+-175. The isotopic exchange reaction for 12C12C is too slow to significantly alter the 12C12C/12C13C ratio and the 12C12C to 12C13C ratio a good measure of half the carbon isotope ratio: 12C/13C=2 X 12C12C/12C13C=72+-26. A fit of the 12C12C excitation model of van Dishoeck & Black (1982) to the relative population distribution of 12C12C yields n sigma / I = 3.3 +- 1.0 X 1e-14. At r=1e16cm this translates in n=1.7e7cm-3 and dM/dt=2.5e-4Msol/year.
A DNA biosensor based on resonance light scattering using unmodified gold bipyramids
We report on a novel biosensor for determining sequence-specific DNA. It is based on resonance light scattering (RLS) caused by the aggregation of gold bipyramids. These display localized surface plasmon resonance and can be used as a bioprobe. The absorption spectra and the transmission electron micrographs provide visual evidence of the aggregation of the gold bipyramids in the presence of DNA. The RLS intensity of the gold bipyramids increases with the concentration of the target DNA. The method was successfully applied to the determination of a 30-mer single-stranded oligonucleotide and works over the 0.1-10 nM concentration range. (author)
Evidence for a scalar $\\kappa(900)$ resonance in $\\pi$-K scattering
Black, D; Sannino, F; Schechter, J
1998-01-01
Motivated by the $1/N_c$ expansion, we study a simple model in which the pi-K scattering amplitude is the sum of a current-algebra contact term and resonance pole exchanges. This phenomenological model is crossing symmetric and, when a putative light strange scalar meson, kappa, is included, satisfies the unitarity bounds to well above 1 GeV. The model also features chiral dynamics, vector meson dominance and appropriate interference between the established scalar K*(1430) resonance and its predicted background. We briefly discuss the physical significance of the results and directions for further work.
Collision times in pi-pi and pi-K scattering and spectroscopy of meson resonances
Kelkar, N G; Khemchandani, K P
2003-01-01
Using the concept of collision time (time delay) introduced by Eisenbud and Wigner and its connection to on-shell intermediate unstable states, we study mesonic resonances in pi-pi and pi-K scattering. The time-delay method proves its usefulness by revealing the spectrum of the well-known rho- and K*-mesons and by supporting some speculations on rho-mesons in the 1200 MeV region. We use this method further to shed some light on more speculative meson resonances, among others the enigmatic scalars. We confirm the existence of chiralons below 1 GeV in the unflavoured and strange meson sector.
Role of negative ion resonances in electron scattering from atoms and molecules
Transient negative ions (resonances) formed during the collision of an electron with an atom or molecule have been extensively studied for over thirty years. The continued interest in these states, both experimentally and theoretically, stems from the profound effects that they can have on electron scattering cross sections and the role that electron-electron correlations play in their formation and quasi-stability. A selective discussion of examples of such resonances, involving one, two and three excited electrons is given for a wide range of atomic and molecular systems. Copyright (1999) CSIRO Australia
Forward dispersion relations for pion-kaon scattering and the K*0(800) resonance
Rodas, A
2016-01-01
We review our recent analysis of $\\pi K$ scattering data in terms of forward dispersion relations, and also present the parameters of the strange resonances. This work consists of fits to the data that are constrained to satisfy analyticity requirements. The method yields a set of simple and consistent parameterizations that are compatible with forward dispersion relations up to 1.6 GeV while still describing the data. We also obtain the pole parameters of the $K^*_0(800)$ and the $K^*(892)$ resonances.
Resonance scattering in the X-ray emission lines profiles of ζ Puppis
Leutenegger, M. A.; Cohen, D. H.; Kahn, S. M.; Owocki, S. P.; Paerels, F. B. S.
2008-01-01
We present XMM-Newton Reflection Grating Spectrometer observations of pairs of X-ray emission line profiles from the O star ζ Pup that originate from the same He-like ion. The two profiles in each pair have different shapes and cannot both be consistently fit by models assuming the same wind parameters. We show that the differences in profile shape can be accounted for in a model including the effects of resonance scattering, which affects the resonance line in the pair but not the intercombi...
Resonance scattering in the X-ray emission line profiles of Zeta Puppis
Leutenegger, M. A.; Cohen, D. H.; Kahn, S. M.; Owocki, S. P.; Paerels, F. B. S.
2007-01-01
We present XMM-Newton Reflection Grating Spectrometer observations of pairs of X-ray emission line profiles from the O star Zeta Pup that originate from the same He-like ion. The two profiles in each pair have different shapes and cannot both be consistently fit by models assuming the same wind parameters. We show that the differences in profile shape can be accounted for in a model including the effects of resonance scattering, which affects the resonance line in the pair but not the interco...
Roca, L
2012-01-01
We present a way to evaluate the scattering of unstable particles quantized in a finite volume with the aim of extracting physical observables for infinite volume from lattice data. We illustrate the method with the $\\pi\\rho$ scattering which generates dynamically the axial-vector $a_1(1260)$ resonance. Energy levels in a finite box are evaluated both considering the $\\rho$ as a stable and unstable resonance and we find significant differences between both cases. We discuss how to solve the problem to get the physical scattering amplitudes in the infinite volume, and hence phase shifts, from possible lattice results on energy levels quantized inside a finite box.
The 12C + 12C + α three-body final state induced by the 12C + 16O entrance channel
A kinematically-complete experiment has been made of the 12C + 16O → 12C + 12C + α reaction in the range of bombarding energies between 68 and 80 MeV. The double cross section was measured by observing two 12C nuclei in the time coincidence mode at 300 with respect to the beam in a symmetrical coplaner geometry. It is clarified that the reaction mainly proceeds through sequential decay involving the formation of the 4+ 10.35- and 6+ 14.82- MeV states of 16O. The double cross section for these sequential decays exhibits a marked enhancement at 70 MeV superposed on a large continuous background. In a Hauser-Feshbach analysis, the continuous background of the differential and double cross sections is successfully reproduced for the 4+ 10.35-MeV state of 16O. The 12C-12C angular correlation measured at 77 MeV shows a significant discrepancy between the experimental data and the Hauser-Feshbach prediction. (author)
We intend to measure the structure of the unbound nucleus $^{21}$Al via resonance elastic and inelastic scattering with an active target. There are many goals: \\\\ a) to locate the 1/2$^{+}$ level in $^{21}$Al that brings information on the Thomas-Ehrman shift, \\\\ b) to measure the energy spectrum of $^{21}$Al which is a N=8 isotone with the resonance elastic scattering reaction, \\\\ c) to investigate via inelastic scattering the strength of core excitations in the existence of narrow unbound resonances beyond the proton drip-line.
Importance of resonance widths in low-energy scattering of weakly-bound light-mass nuclei
Fraser, P R; Amos, K; Bray, I; Canton, L; Fossion, R; Kadyrov, A S; Karataglidis, S; Svenne, J P; van der Knijff, D
2016-01-01
What effect do particle-emitting resonances have on the scattering cross section? What physical considerations are necessary when modelling these resonances? These questions are important when theoretically describing scattering experiments with radioactive ion beams which investigate the frontiers of the table of nuclides, far from stability. Herein, a novel method is developed that describes resonant nuclear scattering from which centroids and widths in the compound nucleus are obtained when one of the interacting bodies has particle unstable resonances. The method gives cross sections without unphysical behavior that is found if simple Lorentzian forms are used to describe resonant target states. The resultant cross sections differ significantly from those obtained when the states in the coupled channel calculations are taken to have zero width, and compound-system resonances are better matched to observed values.
Study of resonances in 16O, 28Si elastic scattering near the Coulomb barrier
The 28Si + 16O elastic scattering has been studied above the Coulomb barrier. Height angular distributions has been measured and analyzed between 18.67 MeV and 22.29 MeV center of mass energy. An optical model analysis shows that the very deep and transparent potentials reproduce the oscillations at back angles of the angular distributions. This result is confirmed by a coupled equation analysis of the elastic and inelastic scattering of the first 2+ state of 28Si. A semi-classical analysis shows a pole in these very transparent optical potentials. An analysis with only one Regge pole by angular distribution reproduces perfectly the data. An phase shift analysis confirms the presence of resonant quasi-molecular states of short lifetime with overlapping width to explain the first structure observed in the excitation function measured at 1800 in the center of mass. A spin value has been assigned at these resonant states
Supernova Resonance--scattering Line Profiles in the Absence of a Photosphere
Friesen, Brian; Branch, David; Chen, Bin; Parrent, Jerod T; Thomas, R C
2012-01-01
In supernova spectroscopy relatively little attention has been given to the properties of optically thick spectral lines in epochs following the photosphere's recession. Most treatments and analyses of post-photospheric optical spectra of supernovae assume that forbidden-line emission comprises most if not all spectral features. However, evidence exists which suggests that some spectra exhibit line profiles formed via optically thick resonance-scattering even months or years after the supernova explosion. To explore this possibility we present a geometrical approach to supernova spectrum formation based on the "Elementary Supernova" model, wherein we investigate the characteristics of resonance-scattering in optically thick lines while replacing the photosphere with a transparent central core emitting non-blackbody continuum radiation, akin to the optical continuum provided by decaying 56Co formed during the explosion. We develop the mathematical framework necessary for solving the radiative transfer equation...
Resonance Light Scattering Spectra of Silver Thiocyanate System and its Application in Analysis
Chang Yin LU; Zhi Hui HAN; Sheng Yuan YANG
2005-01-01
A novel determination method of Ag+ was established. In acetic acid-sodium acetate buffer (pH 5.0) medium, Ag+ reacts with SCN- to form AgSCN in the presence of TritonX-100,which results in an increase of resonance light scattering (RLS) and giving a new RLS spectrum.The maximum RLS peak was at 585 nm. The enhancement of resonance light scattering at 585nm was proportional to the concentration of Ag+ ranging from 0.0045-4.00 μg mL-1 (r=0.9991),and the detection limit was 1.37 ng mL-1 with the recovery of 97.70%～104.80%.
X-ray resonance scattering in a spherically symmetric coronal model
Haisch, B. M.; Claflin, E. S.
1985-01-01
In the solar corona the opacities of some of the prominent X-ray emission lines are on the order of tau of about I over typical coronal path lengths. A particular solution of the radiative transfer problem involving an extended, spherically symmetric coronal shell radiating isotropic, homogeneous emission in which single-scattering also takes place is presented and discussed. Within the context of this simplified model, it is found that scattered radiation is an important contribution to the total emergent resonance line flux and that for the He-like family of resonance (r), intercombination (i), and forbidden (f) lines, the ratio G = (f + i)/r would decrease as a function of optical depth for disk-center emission in an extended spherically symmetric corona.
Choi, M S; Lee, S H
1999-01-01
The inherent background coefficients that exactly describe the background amplitudes in the scattered field have been presented for the scattering of plane acoustic waves by a system of concentrically multilayered solid and/or fluid shells submerged in a fluid. The coefficients have been obtained by replacing the mechanical surface admittance function with the zero-frequency limit of the admittance function for the analogous fluid system, where the shear wave speeds in the solid layers are set to zero. By taking advantage of the concept of incoming and outgoing waves, we find the surface admittance function for the fluid system in such a form that the analytical generalization for any number of layers and the physical interpretation are very easy. The background coefficients obtained are independent of the bulk wave speeds in the system: they depend on the mass densities and the thickness of the shells. With increasing frequency, the inherent background undergoes a transition from the soft to the rigid backgr...
Spin degrees of freedom in electron nucleon scattering in the resonance region
Some aspects of using polarized electrons and/or polarized targets in electron-nucleon scattering experiments are discussed. Polarization measurements can be used to extend the knowledge of nucleon form-factor measurements to higher Q2 and are indispensable for a model-independent extraction of the helicity amplitudes of exclusive meson production. Measurements of polarization asymmetries may also help in revealing the excitation of weaker resonances
TANG XiaoLing; LIU ZhongFang; LIU ShaoPu; HU XiaoLi
2007-01-01
In pH 4.5 Britton-Robinson (BR) buffer solution, erythrosin (ET) can react with diphenhydramine (DP) to form a 1:1 ion-association complex, which not only results in the change of the absorption spectra, but also results in the great enhancement of resonance Rayleigh scattering (RRS) and the quenching of fluorescence. Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 580 nm.In this work, the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reaction and the properties of an analytical chemistry were investigated. A sensitive, simple and new method for the determination of DP by using erythrosin as a probe has been developed. The detection limits for DP were 0.0020 μg/mL for RRS method, 0.088 μg/mL for absorption method and 0.094 μg/mL for fluorophotometry. There was a linear relationship between the absorbance, RRS and fluorescence intensities and the drug concentration in the range of 0.0067-2.0, 0.29-6.4 and 0.31-3.2 μg/mL, respectively. The effects of the interaction of diphenhydramine and erythrosin on the absorption, fluorescence and resonance Rayleigh scattering spectra were discussed. In light polarization experiment, the polarization of RRS at maximum wavelength was measured to be P = 0.9779, and it revealed that the RRS spectrum of DP-ET complex consists mostly of resonance scattering and few resonance fluorescence. In this study, enthalpy of formation and mean polarizability were calculated by AM1 quantum chemistry method. In addition, the reaction mechanism and the reasons for the enhancement of scattering spectra and the energy transfer between absorption, fluorescence and RRS were discussed.
Effect of 56Fe resonance scattering in the central flux of ZPR6-7
The result obtained in early calculations, where a depletion was observed due to the 56Fe resonance scattering (28,8 KeV), in the central flux calculated for the ZPR6-7 critical assembly, when the scheme of ETOE-MC**2-UNIMUG calculation is used, and the out of appearance of these depletion, when the scheme of NJOY-ANISIN calculation is used, is explained. (M.C.K.)
Direct probe of anisotropy in atom-molecule collisions via quantum scattering resonances
Klein, Ayelet; Shagam, Yuval; Skomorowski, Wojciech; Żuchowski, Piotr. S.; Pawlak, Mariusz; Janssen, Liesbeth M. C.; Moiseyev, Nimrod; van de Meerakker, Sebastiaan Y. T.; van der Avoird, Ad; Koch, Christiane P.; Narevicius, Edvardas
2016-01-01
Anisotropy is a fundamental property of particle interactions. It occupies a central role in cold and ultra-cold molecular processes, where long range forces have been found to significantly depend on orientation in ultra-cold polar molecule collisions. Recent experiments have demonstrated the emergence of quantum phenomena such as scattering resonances in the cold collisions regime due to quantization of the intermolecular degrees of freedom. Although these states have been shown to be sensi...
Alpha clustering in Ti isotopes: 40,44,48Ca + α resonant scattering
Bailey Sam
2016-01-01
Full Text Available Measurements were made of the 4He(40,44,48Ca,α resonant scattering reactions at 180° and up to Ec.m. ~ 11.5MeV, using the Thick Target Inverse Kinematics technique. These measurements are discussed, with a focus on assessing their usefulness for investigating α-clustering in medium mass 44,48,52Ti nuclei.
Microscopic theory of resonant soft x-ray scattering in systems with charge order
Benjamin, David Isaiah; Abanin, Dmitry; Abbamonte, Peter; Demler, Eugene A.
2012-01-01
We present a microscopic theory of resonant soft-x-ray scattering that accounts for the delocalized character of valence electrons. Unlike past approaches based on local form factors, our functional determinant method treats realistic band structures. This method builds upon earlier theoretical work in mesoscopic physics and accounts for excitonic effects as well as the orthogonality catastrophe arising from interaction between the core hole and the valence band electrons. We show that the tw...
Simon Schreck; Annette Pietzsch; Brian Kennedy; Conny Såthe; Miedema, Piter S.; Simone Techert; Strocov, Vladimir N.; Thorsten Schmitt; Franz Hennies; Jan-Erik Rubensson; Alexander Föhlisch
2016-01-01
Thermally driven chemistry as well as materials’ functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at ...
Desorption of Rb and Cs from PDMS induced by non resonant light scattering
Simultaneous light-induced desorption of rubidium and cesium atoms has been observed in poly-dimethyl-siloxane (PDMS) coated Pyrex cells at room temperature and at low light intensity. The two alkali atoms show the same dynamics and the same dependence on the de-sorbing light frequency. No competition in the free sites occupancy exists. An interpretation of the experimental results in terms of non-resonant light scattering from the PDMS coating is discussed. (authors)
Measuring velocity of sound with nuclear resonant inelastic x-ray scattering
Hu, Michael Y.; Sturhahn, Wolfgang; Toellner, Thomas S.; Mannheim, Philip D.; Brown, Dennis E.; Zhao, Jiyong; Alp, E. Ercan
2002-01-01
Nuclear resonant inelastic x-ray scattering is used to measure the projected partial phonon density of states of materials. A relationship is derived between the low-energy part of this frequency distribution function and the sound velocity of materials. Our derivation is valid for harmonic solids with Debye-like low-frequency dynamics. This method of sound velocity determination is applied to elemental, composite, and impurity samples which are representative of a wide variety of both crysta...
REX: A Monte Carlo simulation of thick gas target resonant scattering reactions
Curtis, N., E-mail: n.curtis@bham.ac.uk; Walshe, J.
2015-10-11
A Monte Carlo code has been developed to simulate resonant scattering reactions using the thick gas target technique in inverse kinematics. Results are presented for the {sup 4}He({sup 20}Ne,α){sup 20}Ne reaction at 70 MeV, and compared to an experimental measurement which utilised an array of segmented silicon strip detectors. In the case studied, angular straggling in the chamber window is found to dominate the excitation energy resolution.
Resonant magnetic X-ray scattering from in situ grown holmium-metal films
Resonant magnetic X-ray scattering (RMXS) experiments at the Ho-L3 and M5 thresholds have been performed on thin holmium-metal films grown in situ in ultra-high vacuum on W(110). The experimental set-up for these experiments as well as results for the magnetic structure of these films will be described. The magnetic structure stays bulk-like down to a thickness of 14 monolayers. (authors)
Redistribution of light frequency by multiple scattering in a resonant atomic vapor
Carvalho, J C de A; Oriá, M; Chevrollier, M; de Silans, T Passerat
2015-01-01
The propagation of light in a resonant atomic vapor can \\textit{a priori} be thought of as a multiple scattering process, in which each scattering event redistributes both the direction and the frequency of the photons. Particularly, the frequency redistribution may result in L\\'evy flights of photons, directly affecting the transport properties of light in a resonant atomic vapor and turning this propagation into a superdifusion process. Here, we report on a Monte-Carlo simulation developed to study the evolution of the spectrum of the light in a resonant thermal vapor. We observe the gradual change of the spectrum and its convergence towards a regime of Complete Frequency Redistribution as the number of scattering events increases. We also analyse the probability density function of the step length of photons between emissions and reabsorptions in the vapor, which governs the statistics of the light diffusion. We observe two different regime in the light transport: superdiffusive when the vapor is excited n...
Resonant elastic X-ray scattering in chemistry and materials science
Helliwell, J. R.; Helliwell, M.; Kaucic, V.; Logar, N. Z.
2012-06-01
The applications of anomalous scattering for locating metal atoms and discriminating between different elements has increased when optimised with synchrotron X-radiation.The on-resonance effect enhances the targeted elemental signal and allows small occupancies to be determined, including in situations of a mixed metal population at a single atomic site. Thus the applications of resonant elastic X-ray scattering in biological, inorganic and materials chemistry is being widely applied to single crystals, which is our emphasis, but also powders, fibres, solutions, amorphous and thin film states of matter. Recent developments have included the use of high photon energies (upto 100 keV) as well as softer X-rays (2 keV). The various instrument and technical capabilities have improved in the last 15 years. This ease of measurement of the resonant scattering signals along with absorption edge shifts indicates an expansion to the measurement of multiple data sets, to allow monitoring of redox changes. Whilst crystal structure determination in biological crystallography has been revolutionised by the MAD method, it is not a requirement for chemical or materials crystallography, as other phasing techniques are routine. Synchrotron source upgrades will allow nano-sized X-ray beams to be more widely available. The new X-ray lasers suggest new capabilities too.
Resonance Raman scattering and excitonic spectra in TlInS{sub 2} crystals
Zalamai, V.V. [Institute of Applied Physics, Academy of Sciences of Moldova, 5 Academy Street, 2028 Chisinau, Republic of Moldova (Moldova, Republic of); Stamov, I.G. [T.G. Shevchenko State University of Pridnestrovie, 25 Oktyabrya Street 107, 3300 Tiraspol, Republic of Moldova (Moldova, Republic of); Syrbu, N.N., E-mail: sirbunn@yahoo.com [Technical University of Moldova, 168 Stefan cel Mare Avenue, 2004 Chisinau, Republic of Moldova (Moldova, Republic of); Ursaki, V.V. [Institute of Applied Physics, Academy of Sciences of Moldova, 5 Academy Street, 2028 Chisinau, Republic of Moldova (Moldova, Republic of); Dorogan, V. [Technical University of Moldova, 168 Stefan cel Mare Avenue, 2004 Chisinau, Republic of Moldova (Moldova, Republic of)
2015-04-15
The excitons ground and excited states for E∥a and E∥b polarizations in absorption and reflection spectra of TlInS{sub 2} crystals were detected. The fundamental parameters of excitons and bands were determined at k=0. The resonance Raman spectra were investigated in the region of excitons transitions. The resonance Raman scattering spectra with participation of optical phonons that are active at the center of Brillouin zone were identified. The Raman scattering in Y(YX)Z and Y(ZX)Z geometries at 10 K with excitation by He–Ne laser was researched. Energies of phonons with A{sub g} and B{sub g} symmetries were determined. It was shown that the number of modes at 10 K was two times lower than expected according to theoretical calculations. - Highlights: • The resonance Raman scattering in geometry Y(YX)Z and Y(ZX)Z at 10 K was investigated. • Energies of phonons with A{sub g} and B{sub g} symmetries were determined. • The experimental and theoretical calculations completely conform if crystals are described by symmetry group D{sub 4h}{sup 15}. • The main parameters of excitons and bands were determined. • The model of electron transitions in k=0 was suggested.
Martinez Q, E.; Aguilera, E.F.; Rosales, P. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)
2002-07-01
A fusion process analysis of the {sup 12} C + {sup 12} C reaction is done, using the LILITA program. The analysis consisted mainly in varying the value of the Levels density parameter, determining on this way the value of such parameter which reproduces better the contribution of the different channels of fusion-evaporation of particles for this system at different energies. Moreover a comparison with measures done in the Instituto Nacional de Investigaciones Nucleares is realized. (Author)
Diffuse Surface Scattering in the Plasmonic Resonances of Ultra-Low Electron Density Nanospheres
Monreal, R Carmina; Apell, S Peter
2015-01-01
Localized surface plasmon resonances (LSPRs) have recently been identified in extremely diluted electron systems obtained by doping semiconductor quantum dots. Here we investigate the role that different surface effects, namely electronic spill-out and diffuse surface scattering, play in the optical properties of these ultra-low electron density nanosystems. Diffuse scattering originates from imperfections or roughness at a microscopic scale on the surface. Using an electromagnetic theory that describes this mechanism in conjunction with a dielectric function including the quantum size effect, we find that the LSPRs show an oscillatory behavior both in position and width for large particles and a strong blueshift in energy and an increased width for smaller radii, consistent with recent experimental results for photodoped ZnO nanocrystals. We thus show that the commonly ignored process of diffuse surface scattering is a more important mechanism affecting the plasmonic properties of ultra-low electron density ...
Electroweak coupling measurements from polarized Bhabha scattering at the Z0 resonance
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
4 f excitations in Ce Kondo lattices studied by resonant inelastic x-ray scattering
Amorese, A.; Dellea, G.; Fanciulli, M.; Seiro, S.; Geibel, C.; Krellner, C.; Makarova, I. P.; Braicovich, L.; Ghiringhelli, G.; Vyalikh, D. V.; Brookes, N. B.; Kummer, K.
2016-04-01
The potential of resonant inelastic soft x-ray scattering to measure 4 f crystal electric-field excitation spectra in Ce Kondo lattices has been examined. Spectra have been obtained for several Ce systems and show a well-defined structure determined by crystal-field, spin-orbit, and charge-transfer excitations only. The spectral shapes of the excitation spectra can be well understood in the framework of atomic multiplet calculations. For CeCu2Si2 we found notable disagreement between the inelastic x-ray-scattering spectra and theoretical calculations when using the crystal-field scheme proposed from inelastic neutron scattering. Modified sets of crystal-field parameters yield better agreement. Our results also show that, with the very recent improvements of soft x-ray spectrometers in resolution to below 30 meV at the Ce M4 ,5 edges, resonant inelastic x-ray scattering could be an ideal tool to determine the crystal-field scheme in Ce Kondo lattices and other rare-earth compounds.
DUAN Hui; LIU Zhong-Fang; LIU Shao-Pu; KONG Ling
2008-01-01
Heated in a boiling water bath, penicillin antibiotics such as amoxicillin, ampicillin, sodium cloxacillin, sodium carbenicillin and sodium benzylpenicillin could react with K3[Fe(CN)6] to form combined products in a dilute HCl medium.As a result, resonance Rayleigh scattering (RRS) intensity was enhanced greatly and new RRS spectra appeared.The maximum scattering wavelengths of the five combined products are all located at 330 nm.The scattered intensity increments (△I) of the combined products are directly proportional to the concentrations of the antibiotics in a certain range.The methods exhibit high sensitivity, and the detection limits for the five penicillin antibiotics are between 4.61 and 5.62 ng·mL-1.The spectral characteristics of RRS and the optimum reaction conditions were investigated.The mechanism of reaction and the reasons for the enhancement of resonance light scattering were discussed.The effects of coexisting substances have been examined, and the results indicated that the method had a good selectivity.It can be applied to the determination of penicillin antibiotics in capsule, tablet, human serum and urine samples.
An Effective Math Model for Eliminating Interior Resonance Problems of EM Scattering
Zhang Yun-feng
2015-01-01
Full Text Available It is well-known that if an E-field integral equation or an H-field integral equation is applied alone in analysis of EM scattering from a conducting body, the solution to the equation will be either nonunique or unstable at the vicinity of a certain interior frequency. An effective math model is presented here, providing an easy way to deal with this situation. At the interior resonant frequencies, the surface current density is divided into two parts: an induced surface current caused by the incident field and a resonance surface current associated with the interior resonance mode. In this paper, the presented model, based on electric field integral equation and orthogonal modal theory, is used here to filter out resonant mode; therefore, unique and stable solution will be obtained. The proposed method possesses the merits of clarity in concept and simplicity in computation. A good agreement is achieved between the calculated results and those obtained by other methods in both 2D and 3D EM scattering.
On stabilization of scattering resonances in recombination reaction that forms ozone
Ivanov, Mikhail V.; Babikov, Dmitri
2016-04-01
Calculations of energy transfer in the recombination reaction that forms ozone are carried out within the framework of the mixed quantum/classical theory and using the dimensionally reduced 2D-model of ozone molecule, with bending motion neglected. Recombination rate coefficients are obtained at room temperature for symmetric and asymmetric isotopomers of singly and doubly substituted isotopologues. The processes of resonance formation, spontaneous decay, collisional dissociation, and stabilization by bath gas (Ar) are all characterized and taken into account within the steady-state approximation for kinetics. The focus is on stabilization step, where the mysterious isotopic η-effect was thought to originate from. Our results indicate no difference in cross sections for stabilization of scattering resonances in symmetric and asymmetric isotopomers. As practical results, the general and simple analytic models for stabilization and dissociation cross sections are presented, which can be applied to resonances in any ozone molecule, symmetric or asymmetric, singly or doubly substituted. Present calculations show some isotope effect that looks similar to the experimentally observed η-effect, and the origin of this phenomenon is in the rates of formation/decay of scattering resonances, determined by their widths, that are somewhat larger in asymmetric isotopomers than in their symmetric analogues. However, the approximate two-dimensional model used here is insufficient for consistent and reliable description of all features of the isotopic effect in ozone. Calculations using an accurate 3D model are still needed.
Lower hybrid wave resonance cone detection via CO2 laser scattering
Lower hybrid waves are studied in the Princeton ACT-I steady-state toroidal plasma device using a radially scanning CO2 laser scattering system with both amplitude and phase sensitive detection techniques. Clearly defined resonance cones launched from external electrostatic antennas are seen to disappear as the plasma density is raised. Scaling of LHW laser signal with RF power in the presence of resonance cones shows nonlinearities associated with RF induced changes in the effective laser scattering volume. Absolute fluctuation level estimates suggest this occurs when e PHI/T/sub e/ greater than or equal to 1. Wavefront curvature effects can cause a complete loss of resonance cone laser signals, even though probes indicate that cones are still present. Measurements of the wave k/sub perpendicular/-spectrum in the plasma show direct evidence for electron Landau filtering of the original wave k/sub parallel/-spectrum launched from the antenna at the plasma edge, and strong dependence on antenna phasing. Finally, frequency shifts and loss of the resonance cone signal are associated with high levels of plasma density edge turbulence
Extending resonant inelastic X-ray scattering to the extreme ultraviolet
L. Andrew eWray
2015-05-01
Full Text Available In resonant inelastic X-ray scattering (RIXS, core hole resonance modes are used to enhance coupling between photons and low energy electronic degrees of freedom. Resonating with shallow core holes accessed in the extreme ultraviolet (EUV can provide greatly improved energy resolution at standard resolving power, but has been found to often yield qualitatively different spectra than similar measurements performed with higher energy X-rays. This paper uses experimental data and multiplet-based numerical simulations for the M-edges of Co-, Ni- and Cu-based Mott insulators to review the properties that distinguish EUV RIXS from more commonly performed higher energy measurements. Key factors such as the origin of the strong EUV elastic line and advantages of EUV spectral functions over soft X-ray RIXS for identifying intrinsic excitation line shapes are discussed.
Scattering properties of vein induced localized surface plasmon resonances on a gold disk
Amin, Muhammad
2011-12-01
It is demonstrated via simulations that a gold nano-disk with a non-concentric cavity supports localized surface plasmon resonances over a frequency band that includes the visible and the near-infrared parts of the spectrum. The charge distribution on the disk indicates that the two distinct peaks in the scattering cross section are due to the (hybridized) higher-order plasmon modes; plasmon hybridization that involves the dipole modes of the disk and the cavity enforces the "coupling" of the plane-wave excitation to the originally-dark higher-order modes. It is further demonstrated that the resonance frequencies can be tuned by varying the radius of the embedded non-concentric cavity. The near-field enhancement observed at these two tunable resonance frequencies suggests that the proposed structure can be used as a substrate in surface enhanced spectroscopy applications. © 2011 IEEE.
Liu, Z. Z.; Zhang, Q.; Xiao, J. J.
2016-01-01
We study the optical properties associated with both the polariton gap and the Bragg gap in periodic resonator-waveguide coupled systems, based on the temporal coupled mode theory and the transfer matrix method. Using the complex band and the transmission spectrum, it is feasible to tune the interaction between multiple Bragg scattering and local resonance, which may give rise to analogous phenomena of electromagnetically induced transparency (EIT). We further design a plasmonic slot waveguide side-coupled with local plasmonic resonators to demonstrate the EIT-like effects in the near-infrared band. Numerical calculations show that realistic amounts of metal Joule loss may destroy the interference and the total absorption is enhanced in the transparency window due to the near zero group velocity of the guiding wave.
Experimental exclusion of neutral resonances in Bhabha scattering at MeV energies
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.)
WU Zhen-Dong; XU Xin-Xing; BAI Chun-Lin; YU Ning; JIA Fei; LIN Cheng-Jian; ZHANG Huan-Qiao; LIU Zu-Hua; YANG Feng; AN Guang-Peng; ZHANG Chun-Lei; ZHANG Gao-Long; JIA Hui-Ming
2009-01-01
The optical potential parameters for the halo nucleus system 6He+12 C are extracted from fits to the measured angular distributions of 11B(7 Li, 6He)12C reaction at energies of 18.3 and 28.3 MeV with distorted-wave Born approximation analysis. The characters of the obtained optical potential parameters are basically consistent with the results extracted from the fits to the elastic-scattering angular distributions in the literature.
Studies of reaction mechanism in {sup 12}C + {sup 12}C system at intermediate energy of 28.7 MeV/N
Magiera, A. [Inst. of Physics, Jagiellonian Univ., Cracow (Poland)
1996-12-31
The reaction mechanism in {sup 12}C + {sup 12}C system at intermediate energy of about 30 MeV/nucleon was studied. The contribution of various reaction mechanisms (inelastic scattering, transfer reactions, compound nucleus reactions, sequential decay following inelastic excitation and transfer) to the total reaction cross section were found. The analysis of inclusive and coincidence spectra shows that sequential fragmentation processes dominate. 100 refs, 45 figs, 1 tab
Local versus nonlocal $\\alpha\\alpha$ interactions in $3\\alpha$ description of $^{12}$C
Suzuki, Y; Descouvemont, P; Fujiwara, Y; Matsumura, H; Orabi, M; Theeten, M
2008-01-01
Local $\\alpha \\alpha$ potentials fail to describe $^{12}$C as a $3\\alpha$ system. Nonlocal $\\alpha \\alpha$ potentials that renormalize the energy-dependent kernel of the resonating group method allow interpreting simultaneously the ground state and $0^+_2$ resonance of $^{12}$C as $3\\alpha$ states. A comparison with fully microscopic calculations provides a measure of the importance of three-cluster exchanges in those states.
Spatial measure of reaction size in proton scattering
Ito, Makoto; Iwasaki, Masataka; Otani, Reiji; Tomita, Masashi
2016-06-01
The microscopic coupled-channel (MCC) calculations for proton + 12C inelastic scattering are performed in the energy range of Ep = 29.95 MeV to 65 MeV. The nuclear interactions for the proton -12C system are constructed from the folding model, which employs the internal wave function of 12C, obtained from the 3α resonating group method (3α RGM), and an effective nucleon-nucleon interaction of the density-dependent Michigan three-range Yukawa (DDM3Y). The MCC calculation with the 3α RGM + DDM3Y nicely reproduces all of the differential cross sections for elastic and inelastic scattering in the angular range of θc.m. = 30° to 120°. We introduce a scattering radius, which characterizes a spatial size of the scattering area, from partial wave decompositions of an angle-integrated cross section. The scattering radii for the elastic scattering and the various inelastic channels, which involve the rotational or vibrational excitations and the 3α excitations in 12C, are derived. We found that the scattering radii for the inelastic channels with a well developed 3α structure are strongly enhanced in comparison to the scattering radii for the elastic and collective channels. This enhancement of the scattering radius for the 3α channel strongly suggests that the scattering radius is sensitive to a size of the intrinsic structure of the finally excited state in the scattering process.
RESONANT X-RAY SCATTERING AS A PROBE OF ORBITAL AND CHARGE ORDERING
Resonant x-ray scattering is a powerful experimental technique for probing orbital and charge ordering. It involves tuning the incident photon energy to an absorption edge of the relevant ion and observing scattering at previously 'forbidden' Bragg peaks, and it allows high-resolution, quantitative studies of orbital and charge order--even from small samples. Further, resonant x-ray scattering from orbitally ordered systems exhibits polarization- and azimuthal-dependent properties that provide additional information about the details of the orbital order that is difficult, or impossible, to obtain with any other technique. In the manganites, the sensitivity to charge and orbital ordering is enhanced when the incident photon energy is tuned near the Mn K absorption edge (6.539 keV), which is the lowest energy at which a 1s electron can be excited into an unoccupied state. In this process, the core electron is promoted to an intermediate excited state, which decays with the emission of a photon. The sensitivity to charge ordering is believed to be due to the small difference in K absorption edges of the Mn3+ and Mn4+ sites. For orbital ordering, the sensitivity arises from a splitting--or difference in the weight of the density of states [239]--of the orbitals occupied by the excited electron in the intermediate state. In the absence of such a splitting, there is no resonant enhancement of the scattering intensity. In principle, other absorption edges in which the intermediate state is anisotropic could be utilized, but the strong dipole transition to the Mn 4p levels--and their convenient energies for x-ray diffraction--make the K edge well-suited to studies of manganites. The Mn 4p levels are affected by the symmetry of the orbital ordering, which makes the technique sensitive to the orbital degree of freedom. Therefore resonant x-ray scattering can be used to obtain important quantitative information concerning the details of this electronic order. Two mechanisms
Quasi-molecular states in the 12C + 16O amd 16O + 16O systems
The quasi-molecular states observed in the 12C + 16O + 16O and 16O systems are described in a diatomic-like molecular picture using a Morse-type bonding potential. The depths of the bonding potentials are found to be 16.7 and 22.8 MeV respectively, with a long range of about 16 fm. Both the bound and resonance states of these potentials are calculated and compare quite well with the observed states. The diatomic-like rotational and vibrational picture of the quasi-molecular states proposed earlier for 12C + 12C system is found to be valid for the 12C + 16O and 16O + 16O systems. In these two systems, the rotational and vibrational characteristics seem to be more strongly pronounced compared with the 12C + 12C system. (Author)
High-resolution neutron transmission and differential elastic scattering measurements have been made on samples of nitrogen from 0.5 eV to 10 MeV at the Oak Ridge Electron Linear Accelerator (ORELA). For the transmission measurement several different detectors were used at various flight path lengths, with high-purity nitrogen gas samples. The data have been corrected for the dead time of the time digitizer and for several small backgrounds. For the scattering measurements six detectors were placed at various angles inside an evacuated scattering chamber at 200 meters from the neutron producing target. The sample was silicon nitride held in a thin graphite container. Scattering from carbon and silicon samples was also measured to correct for these materials and calibrate the relative efficiencies of the scattering detectors. The data have been corrected for dead time and for a constant background. A preliminary analysis has been completed to obtain parameters of the resonances up to 4.8 MeV
Alpha-cluster states populated in 24Mg + 12C
Charged particle and γ-decays in light α-like nuclei are investigated for 24Mg +12C. Various theoretical predictions for the occurrence of superdeformed and hyperdeformed bands associated with resonance structures with low spin are presented. The inverse kinematics reaction 24Mg +12C is studied at Elab(24Mg) = 130 MeV. Exclusive data were collected with the Binary Reaction Spectrometer in coincidence with EUROBALL IV installed at the VIVITRON Tandem facility at Strasbourg. Specific structures with large deformation were selectively populated in binary reactions and their associated γ-decays studied. Coincident events from α-transfer channels were selected by choosing the excitation energy or the entry point via the two-body Q-values. The analysis of the binary reaction channels is presented with a particular emphasis on 20Ne-γ and 16O-γ coincidences. (author)
New γ-ray measurements for 12C+12C sub-Coulomb fusion: Toward data unification
Fusion excitation functions are measured for the α,p, and n evaporation channels in the fusion of the 12C+12C system at center-of-mass energies between 4.42 and 6.48 MeV, with energy steps of 75 keV. The γ-ray technique is used with a new absolute normalization method which is independent of charge collection, allowing one to monitor at the same time the carbon buildup at the target. Discrepancies between previous works are discussed and a simple unification is proposed. Barrier penetration model (BPM) calculations are consistent with a belly-to-belly orientation of the oblate deformed 12C nuclei at the touching point. As in previous works, much structure is seen in the excitation function which is nearly consistent with the positions of resonances reported in the literature for this system. Using BPM predictions for the background excitation function and doing a simultaneous fit of the relevant Breit-Wigner terms in the measured energy region produced a modified set of resonance parameters. The extrapolation of the astrophysical S factor to lower energies is discussed on the basis of the unified data
The reaction 12C + 12C at bombarding energies from 5 to 10 MeV per nucleon
The reaction 12C + 12C has been studied for energies ranging from ELAB = 60 to 120 MeV. The excitation functions and angular distributions were obtained for the elastic (0+, 0+) and inelastic (2+, 0+), (2+, 2+) channels as well as for the transfer channels of one and two nucleons. For the transfer reactions, the feeding of the final bound states was very selective. Narrow correlated structures were found in the transfer and especially in the elastic and inelastic channels. In this energy range, there appears to be a transition from surface transparency to interference phenomena. The optical model in its simplest form is unable to describe the elastic scattering at large angles. This has been interpreted as a consequence of the coupling between the elastic and inelastic channels which is particularly strong of these energies. 80 refs
Observation of Λ-hypernuclei in the reaction 12C(π+,K+)/sub Λ/12C
The observation of Λ-hypernuclear levels in /sub Λ/12C by associated production through the (π+,K+) reaction is reported. Spectrometers used in the measurements are discussed. The /sub Λ/12C excitation energy spectra were recorded at laboratory scattering angles of 5.60, 10.30, and 15.20. The spectra show two major peaks - one attributed to the ground state, and one about 11 MeV higher in excitation. The peak near 11 MeV excitation energy is believed to be almost entirely composed of a multiplet of three J/sup π/ = 2+ states. Relativistic DWBA calculations imply support for the expectation that higher spin states are preferentially populated in the (π+,K+) reaction, compared to the (K-,π-) reaction in which lower spin states are excited. 29 refs., 40 figs
Milner, E.C.
1985-12-01
The observation of ..lambda..-hypernuclear levels in /sub ..lambda..//sup 12/C by associated production through the (..pi../sup +/,K/sup +/) reaction is reported. Spectrometers used in the measurements are discussed. The /sub ..lambda..//sup 12/C excitation energy spectra were recorded at laboratory scattering angles of 5.6/sup 0/, 10.3/sup 0/, and 15.2/sup 0/. The spectra show two major peaks - one attributed to the ground state, and one about 11 MeV higher in excitation. The peak near 11 MeV excitation energy is believed to be almost entirely composed of a multiplet of three J/sup ..pi../ = 2/sup +/ states. Relativistic DWBA calculations imply support for the expectation that higher spin states are preferentially populated in the (..pi../sup +/,K/sup +/) reaction, compared to the (K/sup -/,..pi../sup -/) reaction in which lower spin states are excited. 29 refs., 40 figs.
Study of the influence of chemical binding on resonant absorption and scattering of neutrons
At present time the problem of taking into account of the crystalline binding in the heavy nuclei resonance range is not correctly treated in nuclear data processing codes. The present work deals separately with resonant absorption and scattering of neutrons. The influence of crystalline binding is considered for both types of reactions in the harmonic crystal frame work. The harmonic crystal model is applied to the study of resonant absorption cross sections to show the inconsistency of the free gas model widely in use in reactor neutronics. The errors due to the use of the latter were found to be non negligible. These errors should be corrected by introducing a more elaborated harmonic crystal model in codes for resonances analysis and on the nuclear data processing stage. Currently the influence of crystalline binding on transfer cross section in the resonance domain is taken into account in a naive manner using the model of the free nucleus at rest in the laboratory system. In this work I present a formalism (Uncoupled Phonon Approximation) which permits to consider in more detail the crystalline structure of the nuclear fuel. This formalism shows new features in comparison with the static model. (author)
Ferreira, Aires; Viana-Gomes, J.; Nilsson, Johan; Mucciolo, Eduardo R.; Peres, Nuno M. R.; Castro Neto, Antonio H.
2011-03-01
We show that a coherent picture for the dc conductivity of monolayer and bilayer graphene emerges from considering that strong short-range potentials are the main source of scattering in these two systems. The origin of the strong short range potentials may lie in adsorbed hydrocarbons at the surface of graphene. The equivalence between results based on the partial wave description of scattering, the Lippmann-Schwinger equation, and the T-matrix approach is established. Scattering due to resonant impurities close to the neutrality point is investigated via a numerical computation of the Kubo formula using a kernel polynomial method. We find that realistic adsorbates originate impurity bands in monolayer and bilayer graphene close to the Dirac point. In the midgap region, a plateau of minimum conductivity of about e2 / h (per layer) is induced by the resonant disorder. In bilayer graphene, a large adsorbate concentration can develop an energy gap between midgap states and high energy states. As a consequence, the conductivity plateau is supressed near the edges and a ``conductivity gap'' takes place.
Lorenz-Mie theory for 2D scattering and resonance calculations
Gagnon, Denis
2015-01-01
This PhD tutorial is concerned with a description of the two-dimensional generalized Lorenz-Mie theory (2D-GLMT), a well-established numerical method used to compute the interaction of light with arrays of cylindrical scatterers. This theory is based on the method of separation of variables and the application of an addition theorem for cylindrical functions. The purpose of this tutorial is to assemble the practical tools necessary to implement the 2D-GLMT method for the computation of scattering by passive scatterers or of resonances in optically active media. The first part contains a derivation of the vector and scalar Helmholtz equations for 2D geometries, starting from Maxwell's equations. Optically active media are included in 2D-GLMT using a recent stationary formulation of the Maxwell-Bloch equations called steady-state ab initio laser theory (SALT), which introduces new classes of solutions useful for resonance computations. Following these preliminaries, a detailed description of 2D-GLMT is presente...
Bound and scattering properties in waveguides around free-space Feshbach resonance
Wang, Gaoren; Giannakeas, Panogiotis; Schmelcher, Peter
2016-05-01
The two-body bound and scattering properties in an one-dimensional (1D) harmonic waveguide in the vicinity of free-space magnetic Feshbach resonances are investigated based on the local frame transformation approach. The multichannel characteristics of the interatomic interaction is taken into account. We examine the crossing between the bound state in the waveguide and the ground level of the transverse confinement, i.e. when the bound state crosses the scattering threshold in the waveguide and turns into a continuum state. For s-wave collision, the crossing occurs at the magnetic field where the effective 1D interaction strength g1 D vanishes, and the effective 1D scattering length a1 D diverges. This observation indicates that the molecular formation or atom loss signal in a harmonic waveguide is expected at the magnetic field where a1 D is infinite. Molecule formation is absent at position of the confinement induced resonance which is characterized by the divergence of g1 D . Financial support from Alexander von Humboldt Foundation is acknowledged.
Farnesi, Daniele; Berneschi, Simone; Cosi, Franco; Righini, Giancarlo C; Soria, Silvia; Nunzi Conti, Gualtiero
2016-01-01
Dielectric microspheres can confine light and sound for a length of time through high quality factor whispering gallery modes (WGM). Glass microspheres can be thought as a store of energy with a huge variety of applications: compact laser sources, highly sensitive biochemical sensors and nonlinear phenomena. A protocol for the fabrication of both the microspheres and coupling system is given. The couplers described here are tapered fibers. Efficient generation of nonlinear phenomena related to third order optical non-linear susceptibility Χ((3)) interactions in triply resonant silica microspheres is presented in this paper. The interactions here reported are: Stimulated Raman Scattering (SRS), and four wave mixing processes comprising Stimulated Anti-stokes Raman Scattering (SARS). A proof of the cavity-enhanced phenomenon is given by the lack of correlation among the pump, signal and idler: a resonant mode has to exist in order to obtain the pair of signal and idler. In the case of hyperparametric oscillations (four wave mixing and stimulated anti-stokes Raman scattering), the modes must fulfill the energy and momentum conservation and, last but not least, have a good spatial overlap. PMID:27078752
Jusserand, B.; Fainstein, A.; Ferreira, R.; Majrab, S.; Lemaitre, A.
2011-01-01
We report on confined exciton resonances of acoustic and folded acoustic phonon light scattering in a GaAs/AlAs multi-quantum-well. Significant variations of the line shifts and widths are observed across the resonance and quantitatively reproduced in terms of the polariton dispersion. This high resolution Brillouin study brings new unexpectedly detailed informations on the polariton dynamics in confined systems.
12C(02+)+α molecular states in a microscopic four α model
The 16O nucleus is investigated within a 12C+α four α multicluster model. The generator coordinate method combined with the microscopic R-matrix method is used to determine bound and resonant states. The 12C nucleus is described by 3 α clusters located at the apexes of isosceles triangles. We optimize the generator coordinates to get a reasonable description of the 02+–01+ energy gap, where the 02+ is the so-called Hoyle state, considered as a 3 α state. Our calculations mainly focus on resonances located near the 12C(02+)+α threshold. We emphasize the difficulty to interpret broad resonant states and we show that bound state approximation methods are not well adapted in the context of our study. An R-matrix analysis suggests the existence of 0+, 2+ and 4+ molecular states which present a significant 12C(02+)+α structure, and which may form a rotational band
Theoretical Studies of Direct and Resonant Reactive Scattering Involving Three-Body Systems.
Lutrus, Chen Kwee
The validity of DWBA method is checked to study the direct process for atom-diatomic molecule collisions. The DWBA results for the relative product rotational state distribution for H + D_2 to HD + D are demonstrated to be in good agreement with experimental observations and quasi-classical calculations. Direct comparison between the DWBA and exact close-coupling calculations for the reactive scattering angular distributions of H + H_2 to H_2 + H shows that the structures of angular distribution between the two methods are similar, and the effect of coupling strongly affects the absolute magnitude of cross sections but not the structure of normalized angular distributions. Information theoretic analysis of rotational surprisal is presented for the reactive collision process of H + D_2 to HD + D. Propensity of near linear surprisal at low collision energies and of deviation from linearity at higher collision energies is found. The theoretical formalism of resonance involving three-body systems is presented. Mathematically the three-body quasi-bound state is represented as a linear combination two-body quasi-bound states in terms of each arrangement. Its reduction to the effective two-body representation of the transition amplitude leads to Feshbach's theory of resonance, thus validating our three-body resonant scattering theory. A rigorous derivation of the T matrix is presented to study the effects of direct and resonant reactive scattering processes of e + AB to A + B^-. Analysis of dissociative attachment processes e + H_2 to H + H^- and e + HCl to H + Cl^- is presented, with emphasis on the roles of the direct and resonant processes in the total cross sections. Furthermore, Argand diagram analysis of the transition amplitude for the two dissociative attachment processes is performed. It is found that strong resonance is present in e + HClto H + Cl^-, but not in e + H_2 to H + H^ -. A new recursion relation for the evaluation of overlap between the Morse
Compton scattering in strong magnetic fields: Spin-dependent influences at the cyclotron resonance
Gonthier, Peter L.; Baring, Matthew G.; Eiles, Matthew T.; Wadiasingh, Zorawar; Taylor, Caitlin A.; Fitch, Catherine J.
2014-08-01
The quantum electrodynamical (QED) process of Compton scattering in strong magnetic fields is commonly invoked in atmospheric and inner magnetospheric models of x-ray and soft gamma-ray emission in high-field pulsars and magnetars. A major influence of the field is to introduce resonances at the cyclotron frequency and its harmonics, where the incoming photon accesses thresholds for the creation of virtual electrons or positrons in intermediate states with excited Landau levels. At these resonances, the effective cross section typically exceeds the classical Thomson value by over 2 orders of magnitude. Near and above the quantum critical magnetic field of 44.13 TeraGauss, relativistic corrections must be incorporated when computing this cross section. This profound enhancement underpins the anticipation that resonant Compton scattering is a very efficient process in the environs of highly magnetized neutron stars. This paper presents formalism for the QED magnetic Compton differential cross section valid for both subcritical and supercritical fields, yet restricted to scattered photons that are below pair creation threshold. Calculations are developed for the particular case of photons initially propagating along the field, and in the limit of zero vacuum dispersion, mathematically simple specializations that are germane to interactions involving relativistic electrons frequently found in neutron star magnetospheres. This exposition of relativistic, quantum, magnetic Compton cross sections treats electron spin dependence fully, since this is a critical feature for describing the finite decay lifetimes of the intermediate states. Such lifetimes are introduced to truncate the resonant cyclotronic divergences via standard Lorentz profiles. The formalism employs both the traditional Johnson and Lippmann (JL) wave functions and the Sokolov and Ternov (ST) electron eigenfunctions of the magnetic Dirac equation. The ST states are formally correct for self
A general theory of time dependence of nuclear resonant forward scattering (spatially coherent) as well as 4π-scattering (incoherent) is presented for a system where resonant nuclei are moving diffusively. As in Moessbauer absorption spectroscopy the diffusive motion is taken into account by employing the Van Hove correlation function. However in the case of scattering the role of correlations turns out to be more complicated. The general formulae are obtained and used to analyze the case of free diffusion. 19 refs., 4 figs
Resonant inelastic soft x-ray scattering (RIXS) spectra excited at the 1σg→3σu resonance in gas-phase O2 show excitations due to the nuclear degrees of freedom with up to 35 well-resolved discrete vibronic states and a continuum due to the kinetic energy distribution of the separated atoms. The RIXS profile demonstrates spatial quantum beats caused by two interfering wave packets with different momenta as the atoms separate. Thomson scattering strongly affects both the spectral profile and the scattering anisotropy.
K-edge resonant x-ray magnetic scattering from a transition-metal oxide: NiO
Hill, J.P.; Kao, C.C.; McMorrow, D.F.
1997-01-01
We report the observation of resonant x-ray magnetic scattering in the vicinity of the Ni K edge in the antiferromagnet NiO. An approximately twofold increase in the scattering is observed as the incident photon energy is tuned through a pre-edge feature in the absorption spectrum, associated wit...... quadrupolar (1s-->3d) transitions. No enhancement is observed at the dipolar (1s-->4p) maximum. The quadrupolar resonant scattering amplitude is estimated to be similar to 0.01r(0)....
Lian Hui Chen; Yi Jian; Hong Qun Luo; Shao Pu Liu; Xiao Li Hu
2007-01-01
In an acetic acid-sodium acetate buffer solution of pH 3.6-6.8, a compound complex was formed between sodium hyaluronate (abbreviated as SH) and some basic bisphenylnaphthylmethane dyes, leading to a great enhancement of the intensity of resonance Rayleigh scattering (RRS) and giving a new RRS spectrum, with its maximum scattering peak near 280 nm. It was also found that the intensity of RRS was directly proportional to the concentration of SH near the range between 0 and 3.0 mg/L. Based on these facts, a sensitive method for the determination of SH has been established. The method had good selectivity, and has been used for the determination of total amounts of SH in samples with satisfactory results. For the NB-SH system, the detection limit of SH was down to 13.7 ng/mL.
The reflectance of ceramic YMnO3 formed by randomly oriented large crystallites (average size about 10 µm) was measured at near normal incidence in the spectral range 100–1200 cm−1. A calibration method was used in order to compensate for the effect of diffuse reflection on the surface of the sample. The spectrum was modelled by averaging the single-crystal reflectivity over all possible crystalline orientations. This anisotropy averaging method was found to adequately describe most of the spectrum, but failed in the regions where one of the principal refractive index became smaller than unity. We argue that these discrepancies are due to enhanced resonant scattering, and discuss the effect with the help of a simplified model of independent spheres based on the Mie theory of light scattering. (paper)
The Photochemical Study of HSA and BSA with Resonance Light-Scattering and Fluorescence Spectra
无
2000-01-01
The resonance light-scattering (RLS) of human serum albumin (HSA) and bovine serum albumin (BSA) is reported for the first time, and applied to study photochemical reaction of HSA and BSA. The fact of photocrosslinking self-association effect in HSA and BSA solutions is identified by the enhancement of RLS. The fluorescence quenching at about 350 nm and 700 nm proves that tryptophan (Trp) residues are one of the photochemical activity sites in HSA and BSA molecules. The Rayleigh scattering (RS) spectra of HSA and BSA that were neglected in fluorescence spectra before are found at about 296 nm, 592 nm and 888 nm for the first time, and are of adventageous to studying the aggregation of HSA or BSA. The possible photochemical reaction mechanism is also proposed.
Binding equilibrium of I~- to serum albumin with resonance Rayleigh scattering
梁宏; 沈星灿; 蒋治良; 何锡文; 申泮文
2000-01-01
The binding equilibrium between l- and human serum albumin (HSA) or bovine serum albumin (BSA) has been studied by means of the resonance Rayleigh scattering (RRS) and equilibrium dialysis. It has been found for the first time that RRS and multiple frequency scattering (MFS) are enhanced as the l- binding to the HSA and BSA, but fluorescence quenches. The equilibrium dialysis results suggest that the binding of l- to HSA and BSA fits a phase-distribution model other than Scsitchard model, and that the order of magnitude of its phase-distribution constant was found to be 104. It is most probable that Cl~ or other anion ions influence the binding of P by changing the ionic strength in the solution. The dialysis at different pH indicates that the binding mechanism is due to the electrostatic forces between the T-and protonated basic amino-acid residues.
X-ray resonant exchange scattering of rare-earth nickel borocarbides
Detlefs, C.
1997-10-08
The purpose of this thesis is to investigate the systematics of the microscopic magnetic order within a series of isostructural compounds and, at the same, to develop the relatively young experimental method of x-ray resonant exchange scattering (XRES). In this thesis, the author presents XRES studies of several rare-earth nickel borocarbides, RNi{sub 2}B{sub 2}C. He shows that XRES, similar to the neutron techniques, allows the determination of the orientation of the magnetic moment by measuring the Q-dependence of the scattered intensity of magnetic Bragg reflections. As samples in this study, he chose the recently discovered family of rare-earth nickel borocarbides, RNi{sub 2}B{sub 2}C, which display a wide variety of magnetic structures. Furthermore, in several of these materials, long range magnetic order coexists with superconductivity over some temperature range.
Binding equilibrium of I- to serum albumin with resonance Rayleigh scattering
无
2000-01-01
The binding equilibrium between I- and human serum albumin (HSA) or bovine serum albumin (BSA) has been studied by means of the resonance Rayleigh scattering (RRS) and equilibrium dialysis. It has been found for the first time that RRS and multiple frequency scattering (MFS) are enhanced as the I- binding to the HSA and BSA, but fluorescence quenches. The equilibrium dialysis results suggest that the binding of I- to HSA and BSA fits a phase-distribution model other than Scatchard model, and that the order of magnitude of its phase-distribution constant was found to be 104. It is most probable that Cl- or other anion ions influence the binding of I- by changing the ionic strength in the solution. The dialysis at different pH indicates that the binding mechanism is due to the electrostatic forces between the I- and protonated basic amino-acid residues.
Dubrovich, V K
2016-01-01
Within the framework of a flat cosmological model a propagation of an instantaneous burst of isotropic radiation is considered from the moment of its beginning at some initial redshift z0 to the moment of its registration now (at z=0). We take into account Thomson scattering by free electrons and scattering in La and Lb lines of primordial hydrogen and in lines 1s2 - 1s2p, 1s3p (1S-1P*) of HeI. It is shown that relative amplitude of spectrum distortions caused by scattering in these lines may be from 1000 to 10000 times greater than maximum possible amplitude due to scattering in subordinate lines considered in our previous paper (Dubrovich, Grachev, 2015). In a linear approximation on the optical thickness in the lines the profiles of distortions in resonance lines turn out to be purely in absorption and do not depend on both direction and distance to the burst center in contradistinction to the profiles in subordinate lines. The profiles contain jumps on frequencies corresponding to appearance of a source (...
Chen, Lei; Yu, Zhi; Lee, Youngju; Wang, Xu; Zhao, Bing; Jung, Young Mee
2012-12-21
A rapid and highly sensitive bicinchoninic acid (BCA) reagent-based protein quantitation tool was developed using competitive resonance Raman (RR) and surface-enhanced resonance Raman scattering (SERRS) methods. A chelation reaction between BCA and Cu(+), which is reduced by protein in an alkaline environment, is exploited to create a BCA-Cu(+) complex that has strong RR and SERRS activities. Using these methods, protein concentrations in solutions can be quantitatively measured at concentrations as low as 50 μg mL(-1) and 10 pg mL(-1). There are many advantages of using RR and SERRS-based assays. These assays exhibit a much wider linear concentration range and provide an additional one (RR method) to four (SERRS method) orders of magnitude increase in detection limits relative to UV-based methods. Protein-to-protein variation is determined using a reference to a standard curve at concentrations of BSA that exhibits excellent recoveries. These novel methods are extremely accurate in detecting total protein concentrations in solution. This improvement in protein detection sensitivity could yield advances in the biological sciences and medical diagnostic field and extend the applications of reagent-based protein assay techniques. PMID:23099478
Takemoto, Hiroki; Horiuchi, Hisashi [Kyoto Univ. (Japan). Dept. of Physics; Ono, Akira
1997-05-01
In general, self-conjugate 4n-nuclei have anomalous excited states with the excitation energy 10-15 MeV, which are recognized to be generated by the change of the structure from the shell-model-like one into the cluster one due to the activation of the clustering degrees of freedom. In AMD (Antisymmetrized Molecular Dynamics) fermic nature of nucleons is treated exactly, because the wave function of A-body system is antisymmetrized by a Slater determinant. Hence Pauli principle has been fully incorporated in AMD. As a result, it was concluded that the features of {sup 12}C fragmentation are originated from the activation of alpha-cluster degrees of freedom by indicating the excitation energy spectra of {sup 12}C before its breakup at the dynamical stage. Excitation energy spectrum before {sup 12}C breakup into any fragments consists of two components. One distributes in the range 7-15 MeV and the other in the range above 15 MeV. Accordingly, the features is related to those excited states excited states of {sup 12}C that is considered to have the cluster structure. (G.K.)
Scattering phases for meson and baryon resonances on general moving-frame lattices
Goeckeler, M. [Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Lage, M.; Rusetsky, A. [Bonn Univ. (Germany). Helmholtz-Inst. fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics; Meissner, U.G. [Bonn Univ. (Germany). Helmholtz-Inst. fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics; Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Forschungszentrum Juelich (Germany). Juelich Center for Hadron Physics and JARA - High Performance Computing; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Division; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Zanotti, J.M. [Adelaide Univ., SA (Australia). CSSM, School of Chemistry and Physics
2012-06-15
A proposal by Luescher enables one to compute the scattering phases of elastic two-body systems from the energy levels of the lattice Hamiltonian in a finite volume. In this work we generalize the formalism to S-, P- and D-wave meson and baryon resonances, and general total momenta. Employing nonvanishing momenta has several advantages, among them making a wider range of energy levels accessible on a single lattice volume and shifting the level crossing to smaller values of m{sub {pi}}L.
Inelastic nuclear resonance scattering measurements, utilizing a submilli eV monochromator, were performed on natural Dy metal, dysprosium oxide, and intermetallic Laves and Chevrel phase dysprosium compounds. The inelastic spectrum directly yields the partial phonon density of states, and thus provides a wealth of information about the modes of vibration occurring in a lattice at the Moessbauer Dy site. The extraction of the partial phonon density of states from a broad range of materials containing dysprosium demonstrates the feasibility of material science studies.
Theoretical and experimental study of resonant inelastic X-ray scattering for NiO
Resonant inelastic X-ray scattering (RIXS) spectra for Ni 2p to 3d excitation and 3d to 2p de-excitation of NiO are studied both theoretically and experimentally. Theoretical calculations with a single impurity Anderson model (SIAM) describe the charge transfer (CT) and d-d excitations in RIXS, and detailed study is made for the CT energy. High resolution RIXS measurements reveal the precise d-d excitation structure and its polarization dependence, and they are well reproduced by the SIAM calculation
Theoretical and experimental study of resonant inelastic X-ray scattering for NiO
Kotani, A. [RIKEN Harima Institute, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo, 679-5148 (Japan) and Photon Factory, Institute of Materials Structure Science, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)]. E-mail: kotani@spring8.or.jp; Matsubara, M. [Laboratory of Physics, Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT (Finland); Uozumi, T. [College of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Ghiringhelli, G. [INFM-Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Fracassi, F. [INFM-Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Dallera, C. [INFM-Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Tagliaferri, A. [INFM-Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Brookes, N.B. [European Synchrotron Radiation Facility, B.P. 220, 38043 Grenoble Cedex (France); Braicovich, L. [INFM-Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy)
2006-11-15
Resonant inelastic X-ray scattering (RIXS) spectra for Ni 2p to 3d excitation and 3d to 2p de-excitation of NiO are studied both theoretically and experimentally. Theoretical calculations with a single impurity Anderson model (SIAM) describe the charge transfer (CT) and d-d excitations in RIXS, and detailed study is made for the CT energy. High resolution RIXS measurements reveal the precise d-d excitation structure and its polarization dependence, and they are well reproduced by the SIAM calculation.
Jungmann, C.R.; Weigmann, H. (Commission of the European Communities, Geel (Belgium). Central Bureau for Nuclear Measurements); Mewissen, L.; Poortmans, F. (Centre d' Etude de l' Energie Nucleaire, Mol (Belgium)); Cornels, E. (Rijksuniversitair Centrum te Antwerpen (Belgium)); Theobald, J.P. (Technische Hochschule Darmstadt (Germany, F.R.). Inst. fuer Kernphysik)
1982-09-27
Neutron transmission experiments were performed on /sup 32/S between 0.18 MeV and 19 MeV and differential elastic scattering experiments up to 2 MeV. The resonance parameters, including spin and parity, were determined up to 1.7 MeV. The distribution of neutron strength was determined for ssub(1/2), psub(1/2), psub(3/2), dsub(3/2), dsub(5/2) and f-wave levels, and is compared to recent model calculations. The isotopic purity of some possible T = 3/2 isobaric analog states was deduced from their neutron widths.
Band dispersion of MgB sub 2 , graphite and diamond from resonant inelastic scattering
Sokolov, A V; Leitch, S; Moewes, A; Kortus, J; Finkelstein, L D; Skorikov, N A; Xiao, C; Hirose, A
2003-01-01
The quantitative band mapping for MgB sub 2 , graphite and diamond are realized using resonant inelastic x-ray scattering (RIXS) measurements. RIXS shows distinct dispersive features when the excitation energy is tuned near B 1s and C 1s thresholds, which are assigned to the calculated energy bands using k sup->-momentum conservation. The agreement between experiment and theory suggests that electron-electron interactions are not important for MgB sub 2 , which behaves like a conventional metal and is well described by band theory.
Measuring velocity of sound with nuclear resonant inelastic x-ray scattering
Hu, Michael Y. [Carnegie Inst. of Washington, Argonne, IL (United States). High Pressure Collaborative Access Team (HPCAT); Sturhahn, Wolfgang [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Toellner, Thomas S. [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Mannheim, Philip D. [Univ. of Connecticut, Storrs, CT (United States); E. Brown, Dennis [Northern Illinois Univ., DeKalb, IL (United States). Dept. of Physics; Zhao, Jiyong [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Alp, E. Ercan [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
2003-03-01
Nuclear resonant inelastic x-ray scattering is used to measure the projected partial phonon density of states of materials. A relationship is derived between the low-energy part of this frequency distribution function and the sound velocity of materials. Our derivation is valid for harmonic solids with Debye-like low-frequency dynamics. This method of sound velocity determination is applied to elemental, composite, and impurity samples which are representative of a wide variety of both crystalline and noncrystalline materials. Advantages and limitations of this method are elucidated.
Measuring velocity of sound with nuclear resonant inelastic x-ray scattering
Nuclear resonant inelastic x-ray scattering is used to measure the projected partial phonon density of states of materials. A relationship is derived between the low-energy part of this frequency distribution function and the sound velocity of materials. Our derivation is valid for harmonic solids with Debye-like low-frequency dynamics. This method of sound velocity determination is applied to elemental, composite, and impurity samples which are representative of a wide variety of both crystalline and noncrystalline materials. Advantages and limitations of this method are elucidated
X-ray suppression in gamma-ray bursts through resonant Compton scattering
Brainerd, J. J.
1992-01-01
An X-ray that scatters with an electron in the first Landau level of a strong magnetic field is converted into a gamma ray. This process has a resonant cross section at X-ray energies and is therefore highly likely to occur even when the first Landau level is sparsely populated. Converted X-rays are cyclotron absorbed, maintaining the equilibrium between the cyclotron photon density and the population of the first Landau level. By suppressing a neutron star's black body emission, this mechanism can produce a gamma-ray burst with a low X-ray flux.
Nuclear resonant inelastic X-ray scattering at high pressure and low temperature
Bi, Wenli; Zhao, Jiyong; Lin, Jung-Fu; Jia, Quanjie; Hu, Michael Y.; Jin, Changqing; Ferry, Richard; Yang, Wenge; Struzhkin, Viktor; Alp, E. Ercan
2015-01-01
A new synchrotron radiation experimental capability of coupling nuclear resonant inelastic X-ray scattering with the cryogenically cooled high-pressure diamond anvil cell technique is presented. The new technique permits measurements of phonon density of states at low temperature and high pressure simultaneously, and can be applied to studies of phonon contribution to pressure- and temperature-induced magnetic, superconducting and metal–insulator transitions in resonant isotope-bearing materials. In this report, a pnictide sample, EuFe2As2, is used as an example to demonstrate this new capability at beamline 3-ID of the Advanced Photon Source, Argonne National Laboratory. A detailed description of the technical development is given. The Fe-specific phonon density of states and magnetism from the Fe sublattice in Eu57Fe2As2 at high pressure and low temperature were derived by using this new capability. PMID:25931094
Duan, Sai; Luo, Yi
2015-01-01
The Raman intensity can be well described by the famous Albrecht equation that consists of $A$ and $B$ terms. It has become a textbook knowledge that the contribution from Albrecht's $A$ term can be neglected without loss of accuracy for non-resonant Raman scattering processes. However, as demonstrated in this study, we have found that this widely accepted long-standing assumption fails drastically for totally symmetric vibration modes of molecules. Perturbed first principles calculations for water molecule show that strong constructive interference between the $A$ and $B$ terms occurs for the Raman intensity of the symmetric O-H stretching mode, which can account for about 40% of the total intensity. Meanwhile, a minor destructive interference is found for the angle bending mode. The state to state mapping between the Albrecht's theory and the perturbation theory allows us to verify the accuracy of the widely employed perturbation method for the dynamic/resonant Raman intensities. The model calculations show...
Driven spatially auto resonant stimulated Raman scattering in the kinetic regime
The auto resonant behavior of Langmuir waves excited by stimulated Raman scattering (SRS) is clearly identified in particle-in-cell (PIC) simulations in an inhomogeneous plasma. As previously shown via a 3-wave coupling model [T. Chapman et al., Phys. Plasmas 17, 122317 (2010)], weakly kinetic effects such as trapping can be described via an amplitude-dependent frequency shift that compensates the dephasing of the resonance of SRS due to the inhomogeneity. The autoresonance (AR) leads to phase locking and to growth of the Langmuir wave beyond the spatial amplification expected from Rosenbluth's model in an inhomogeneous profile [M. N. Rosenbluth, Phys. Rev. Lett. 29, 565 (1972)]. Results from PIC simulations and from a 3-wave coupling code show very good agreement, leading to the conclusion that AR arises even beyond the so-called weakly kinetic regime. (authors)
Determination of magnetic-moment directions using x-ray resonant exchange scattering
We present determinations of the magnetic structures of NdNi2B2C and SmNi2B2C by means of x-ray resonant exchange scattering (XRES). The integrated intensity of a number of magnetic reflections was measured as a function of the Bragg angle and compared to model calculations for various magnetic structures. The two compounds were found to have the same magnetic modulation wave vector but different moment directions. A resonant feature observed below the Sm L3-absorption edge, similar to unexplained effects found in other light rare-earth compounds, is identified as quadrupolar XRES and is used to refine the details of the moment direction. copyright 1997 The American Physical Society
Ovchinnikova; Dmitrienko
1999-01-01
Symmetry restrictions on the intensities and polarization properties of main reflections and their satellites are found for incommensurately modulated crystals in the case of anisotropic anomalous X-ray diffraction near absorption edges. It is shown that the modulation becomes a source of additional anisotropy for each resonant scatterer and induces a modulated behaviour of the susceptibility tensor. The four-dimensional approach is used to calculate the set of possible reflections. It is found that additional ('forbidden') reflections may appear both in the system of main reflections and in the system of satellites. The anisotropy also results in complex azimuthal and polarization properties of each reflection. The displacive modulation is discussed in detail. The ATS reflections corresponding to the resonant X-ray diffraction near the K-edge of iron in pyrrhotite-5.5C are considered. PMID:10927227
Proton resonance elastic scattering of $^{30}$Mg for single particle structure of $^{31}$Mg
The single particle structure of $^{31}$Mg, which is located in the so-called “island of inversion”, will be studied through measuring Isobaric Analog Resonances (IARs) of bound states of $^{31}$Mg. They are located in the high excitation energy of $^{31}$Al. We are going to determine the spectroscopic factors and angular momenta of the parent states by measuring the excitation function of the proton resonance elastic scattering around 0 degrees in the laboratory frame with around 3 MeV/nucleon $^{30}$Mg beam. The present study will reveal the shell evolution around $^{32}$Mg. In addition, the spectroscopic factor of the (7/2)$^{−}$ state which was not yet determined experimentally, may allow one to study the shape coexistence in this nucleus.
Yuffa, Alex J; Gutierrez, Yael; Sanz, Juan M; Alcaraz de la Osa, Rodrigo; Saiz, José M; González, Francisco; Moreno, Fernando; Videen, Gorden
2016-03-01
The ability to infer near-field scattering properties from far-field measurements is of paramount importance in nano-optics. Recently we derived an approximate formula for predicting the frequency shift between near- and far-field intensity peaks in the case of a dielectric sphere. In this work we demonstrate that almost an identical formula can be used to predict the resonance shift of a dielectric cylinder and a perfectly conducting cylinder. We find the redshift of the resonance peak of the perfect electric conducting cylinder to be approximately 2 orders of magnitude greater than for the dielectric cylinder. The errors in our approximate analytic formula for predicting the redshift are approximately only twice as great. Furthermore, we apply the redshift formula to a silicon cylinder and discuss its magneto-dielectric properties, which may be of interest in design of metamaterials. PMID:26974908
Leroy, V; Page, J H; Scanlon, M G
2010-01-01
We present experimental results on a model system for studying wave propagation in a complex medium exhibiting low frequency resonances. These experiments enable us to investigate a fundamental question that is relevant for many materials, such as metamaterials, where low-frequency scattering resonances strongly influence the effective medium properties. This question concerns the effect of correlations in the positions of the scatterers on the coupling between their resonances, and hence on wave transport through the medium. To examine this question experimentally, we measure the effective medium wave number of acoustic waves in a sample made of bubbles embedded in an elastic matrix over a frequency range that includes the resonance frequency of the bubbles. The effective medium is highly dispersive, showing peaks in the attenuation and the phase velocity as functions of the frequency, which cannot be accurately described using the Independent Scattering Approximation (ISA). This discrepancy may be explained...
Acoustic scattering by elastic cylinders of elliptical cross-section and splitting up of resonances
The scattering of a plane acoustic wave by an infinite elastic cylinder of elliptical cross section is studied from a modal formalism by emphasizing the role of the symmetries. More precisely, as the symmetry is broken in the transition from the infinite circular cylinder to the elliptical one, the splitting up of resonances is observed both theoretically and experimentally. This phenomenon can be interpreted using group theory. The main difficulty stands in the application of this theory within the framework of the vectorial formalism in elastodynamics. This method significantly simplifies the numerical treatment of the problem, provides a full classification of the resonances, and gives a physical interpretation of the splitting up in terms of symmetry breaking. An experimental part based on ultrasonic spectroscopy complements the theoretical study. A series of tank experiments is carried out in the case of aluminium elliptical cylinders immersed in water, in the frequency range 0 ≤ kr ≤ 50, where kr is the reduced wave number in the fluid. The symmetry is broken by selecting various cylinders of increasing eccentricity. More precisely, the greater the eccentricity, the higher the splitting up of resonances is accentuated. The experimental results provide a very good agreement with the theoretical ones, the splitting up is observed on experimental form functions, and the split resonant modes are identified on angular diagrams
Transparency of 12C for protons
Existing cross-section data for 1p-shell knockout in the reaction 12C(e,e'p)11B --as obtained under different kinematic conditions--are shown to be mutually consistent, apart from a recent measurement performed in Mainz. New data have been collected at the Amsterdam Pulse Stretcher that confirm the normalization of the older measurements. An analysis of the world's 12C(e,e'p)11B data has yielded precise values of the spectroscopic factor for 1p-shell and 1s-shell knockout from 12C. These values have been used to evaluate the transparency of the 12C nucleus for 1p-shell and 1s-shell protons separately on the basis of recent high-energy 12C(e,e'p)11B data taken at a four-momentum transfer squared Q2 of 1.1 (GeV/c)2. As the resulting average value of the nuclear transparency, 0.81±0.04, is considerably higher than the value obtained from previous analyses and theoretical estimates, the high Q2 data were used instead for an independent determination of the spectroscopic strength for 1p+1s knockout. Combining these results with the low Q2 data the spectroscopic factors appear to be momentum-transfer dependent. Possible explanations of these surprising results in terms of reaction-mechanism effects or a possible breakdown of the quasiparticle concept at high Q2 are discussed as well. (c) 2000 The American Physical Society
Tests of carbon targets for 12C+12C reactions at astrophysical energies
As a preliminary step towards measurements of the 12C +12 C reactions at astrophysical energies, we investigate the behaviour of targets under beam bombardment, specifically the quantitative relation between hydrogen and deuterium content of different carbon targets and target temperature. Experiments have taken place at the CIRCE accelerator in Caserta, Italy and preliminary results are presented here
Surface origin and control of resonance Raman scattering and surface band gap in indium nitride
Alarcón-Lladó, Esther; Brazzini, Tommaso; Ager, Joel W.
2016-06-01
Resonance Raman scattering measurements were performed on indium nitride thin films under conditions where the surface electron concentration was controlled by an electrolyte gate. As the surface condition is tuned from electron depletion to accumulation, the spectral feature at the expected position of the (E 1, A 1) longitudinal optical (LO) near 590 cm‑1 shifts to lower frequency. The shift is reversibly controlled with the applied gate potential, which clearly demonstrates the surface origin of this feature. The result is interpreted within the framework of a Martin double resonance, where the surface functions as a planar defect, allowing the scattering of long wavevector phonons. The allowed wavevector range, and hence the frequency, is modulated by the electron accumulation due to band gap narrowing. A surface band gap reduction of over 500 meV is estimated for the conditions of maximum electron accumulation. Under conditions of electron depletion, the full InN bandgap (E g = 0.65 eV) is expected at the surface. The drastic change in the surface band gap is expected to influence the transport properties of devices which utilize the surface electron accumulation layer.
Schreck, Simon; Pietzsch, Annette; Kennedy, Brian; Såthe, Conny; Miedema, Piter S; Techert, Simone; Strocov, Vladimir N; Schmitt, Thorsten; Hennies, Franz; Rubensson, Jan-Erik; Föhlisch, Alexander
2016-01-01
Thermally driven chemistry as well as materials' functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future. PMID:26821751
Simulation and analysis of 13N+p elastic resonance scattering
WANG You-Bao; QIN Xing; WANG Bao-Xiang; LIU Wei-Ping; LI Zhi-Hong; BAI Xi-Xiang; LIAN Gang; GUO Bing; ZENG Sheng; SU Jun; LI Yun-Ju; JIANG Chao
2009-01-01
The 13N+p elastic resonance scattering has been studied at the secondary radioactive beam facility of CIAE in inverse kinematics via a thick-target method. The excitation function for the 13N(p,p) scattering was obtained in the energy interval of Ecm ≈0.5--3.2 MeV with a 13N secondary beam of (47.8±1.5) MeV. Carefulanalysis of the secondary beam components and extensive Monte-Carlo simulations enable the resolution of the experimental proton spectra. The resonance parameters for five low-lying levels in 140 were deduced by R- matrix fitting calculations with MULTI7 and SAMMY-M6-BETA. The present results show general agreement with those from a recent similar work, and thus confirm the observation of a new 0- level at 5.7 MeV in 14O with an improved width of 400(45) keV.
Schreck, Simon; Pietzsch, Annette; Kennedy, Brian; Såthe, Conny; Miedema, Piter S.; Techert, Simone; Strocov, Vladimir N.; Schmitt, Thorsten; Hennies, Franz; Rubensson, Jan-Erik; Föhlisch, Alexander
2016-01-01
Thermally driven chemistry as well as materials’ functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future.
Implantation effects on resonant Raman scattering in CdTe and Cd 0.23Hg 0.77Te
Ramsteiner, M.; Lusson, A.; Wagner, J.; Koidl, P.; Bruder, M.
1990-04-01
We have studied In + implanted CdTe and Cd 0.23Hg 0.77Te by resonant Raman scattering. The laser excitation was in resonance with the EO + Δ O band gap in CdTe or the E1 gap in Cd 0.23Hg 0.77Te. Under these conditions dipole forbidden but defect ind scattering by one longitudinal optical (LO) phonon as well as Fröhlich-induced two-LO phonon scattering is observed. In both cases scattering is found to be strongly affected by ion implantation. In + was implanted at an ion energy of 350 keV with doses ranging from 10 11 to 5×10 14 ions/cm 2. The intensity ratio of the one-LO phonon lines is found to be a quantitative measure of the implantation damage in CdTe and Cd 0.23Hg 0.77Te even for doses as low as 10 11 ions/cm 2. It is shown that the observed effects of implantation damage on resonant Raman scattering by LO phonons are due to a broadening and an energy shift of the corresponding resonances in the Raman scattering efficiency.
Yang, Shin Nan; Tiator, L
2011-01-01
We present the results on P11 resonances obtained with Dubna-Mainz-Taipei (DMT) dynamical model for pion-nucleon scattering and pion electromagnetic production. The extracted values agree well, in general, with PDG values. One pole is found corresponding to the Roper resonance and two more resonances are definitely needed in DMT model. We further find indication for a narrow P11 resonance at around 1700 MeV with a width of around 50 MeV in both pi-N and gamma-pi reactions.
The 12C(12C,α)20Ne and 12C(12C,p)23Na reactions at the Gamow peak via the Trojan Horse Method
Tumino, A.; Spitaleri, C.; Cherubini, S.; Guardo, L.; Gulino, M.; Indelicato, I.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Spartá, R.
2016-05-01
A measurement of the 12C(14N,α20Ne)2H and 12C(14N,p23Na)2Hreactions has been performed at a 14N beam energy of 30.0 MeV. The experiment aims to explore the extent to which contributing 24Mg excited states can be populated in the quasi-free reaction off the deuteron in 14N. In particular, the 24Mg excitation region explored in the measurement plays a key role in stellar carbon burning whose cross section is commonly determined by extrapolating high-energy fusion data. From preliminary results, α and proton channels are clearly identified. In particular, ground and first excited states of 20Ne and 23Na play a major role.
The 12C(12C,α20Ne and 12C(12C,p23Na reactions at the Gamow peak via the Trojan Horse Method
Tumino A.
2016-01-01
Full Text Available A measurement of the 12C(14N,α20Ne2H and 12C(14N,p23Na2Hreactions has been performed at a 14N beam energy of 30.0 MeV. The experiment aims to explore the extent to which contributing 24Mg excited states can be populated in the quasi-free reaction off the deuteron in 14N. In particular, the 24Mg excitation region explored in the measurement plays a key role in stellar carbon burning whose cross section is commonly determined by extrapolating high-energy fusion data. From preliminary results, α and proton channels are clearly identified. In particular, ground and first excited states of 20Ne and 23Na play a major role.
$^{12}$C nuclear reaction measurements for hadrontherapy.
B. Braunn, B; G. Ban, G; J.Colin, J; D. Cussol, D; J.M. Fontbonne, J M; F.R.. Lecolley, F R; C. Pautard, C; Haas, F; Lebhertz, D; Rousseau, M; Stuttge, L; Chevallier, M; Dauvergne, D; Le Foulher, F; Ray, C; Testa, E; Testa, M; Salsac, M D
2010-01-01
Hadrontherapy treatments require a very high precision on the dose deposition ( 2.5% and 1-2mm) in order to keep the benefits of the precise ions’ ballistic. The largest uncertainty on the physical dose deposition is due to ion fragmentation. Up to now, the simulation codes are not able to reproduce the fragmentation process with the required precision. To constraint the nuclear models and complete fragmentation cross sections databases; our collaboration has performed an experiment on May 2008 at GANIL with a 95 MeV/u 12C beam. We have measured the fluence, energy and angular distributions of charged fragments and neutrons coming from nuclear reactions of incident 12C on thick water-like PMMA targets. Preliminary comparisons between GEANT4 (G4BinaryLightIonReaction) simulations and experimental data show huge discrepancies.
When gold nanoparticles were being prepared by sodium citrate reduction method, citrate anions self-assembled on the surface of gold nanoparticles to form supermolecular complex anions with negative charges, and protonated raloxifene (Ralo) was positively charged and could bind with the complex anions to form larger aggregates through electrostatic force and hydrophobic effects, which could result in the remarkable enhancement of the resonance Rayleigh scattering intensity (RRS), and the appearance of new RRS spectra. At the same time, the second-order scattering (SOS) and frequency-doubling scattering (FDS) intensities were also enhanced. The maximum wavelengths were located near 370 nm for RRS, 520 nm for SOS, and 350 nm for FDS, respectively. Among them, the RRS method had the highest sensitivity and the detection limit was 5.60 ng mL-1 for Ralo, and its linear range was 0.05-2.37 μg mL-1. A new RRS method for the determination of trace Ralo using gold nanoparticles probe was developed. The optimum conditions of the reaction and influencing factors were investigated. In addition, the reaction mechanism and the reasons for the enhancement of RRS were discussed
Liu Shaopu; He Youqiu; Liu Zhongfang; Kong Ling; Lu Qunmin [School of Chemistry and Chemical Engineering, Southwest China University, Chongqing 400715 (China)
2007-08-29
When gold nanoparticles were being prepared by sodium citrate reduction method, citrate anions self-assembled on the surface of gold nanoparticles to form supermolecular complex anions with negative charges, and protonated raloxifene (Ralo) was positively charged and could bind with the complex anions to form larger aggregates through electrostatic force and hydrophobic effects, which could result in the remarkable enhancement of the resonance Rayleigh scattering intensity (RRS), and the appearance of new RRS spectra. At the same time, the second-order scattering (SOS) and frequency-doubling scattering (FDS) intensities were also enhanced. The maximum wavelengths were located near 370 nm for RRS, 520 nm for SOS, and 350 nm for FDS, respectively. Among them, the RRS method had the highest sensitivity and the detection limit was 5.60 ng mL{sup -1} for Ralo, and its linear range was 0.05-2.37 {mu}g mL{sup -1}. A new RRS method for the determination of trace Ralo using gold nanoparticles probe was developed. The optimum conditions of the reaction and influencing factors were investigated. In addition, the reaction mechanism and the reasons for the enhancement of RRS were discussed.
Fiber optic particle plasmon resonance sensor based on plasmonic light scattering interrogation
A highly sensitive fiber optic particle plasmon resonance sensor (FO-PPR) is demonstrated for label-free biochemical detection. The sensing strategy relies on interrogating the plasmonic scattering of light from gold nanoparticles on the optical fiber in response to the surrounding refractive index changes or molecular binding events. The refractive index resolution is estimated to be 3.8 x 10-5 RIU. The limit of detection for anti-DNP antibody spiked in buffer is 1.2 x 10-9 g/ml (5.3 pM) by using the DNP-functionalized FO-PPR sensor. The image processing of simultaneously recorded plasmonic scattering photographs at different compartments of the sensor is also demonstrated. Results suggest that the compact sensor can perform multiple independent measurements simultaneously by means of monitoring the plasmonic scattering intensity via photodiodes or a CCD. The potential of using a combination of different kinds of noble metal nanoparticles with different types of functionalized probes in multiple cascaded detection windows on a single fiber to become an inexpensive and ultrasensitive linear-array sensing platform for higher-throughput biochemical detection is provided. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Fiber optic particle plasmon resonance sensor based on plasmonic light scattering interrogation
Lin, H.Y.; Huang, C.H. [Center for Nano Bio-Detection, National Chung Cheng University, 168 University Road, Minhsiung, Chiayi 621 (China); Chau, L.K. [Center for Nano Bio-Detection, National Chung Cheng University, 168 University Road, Minhsiung, Chiayi 621 (China); Department of Chemistry and Biochemistry, National Chung Cheng University, 168 University Road, Minhsiung, Chiayi 621 (China); Advanced Institute of Manufacturing with High-tech Innovations, National Chung Cheng University, 168 University Road, Minhsiung, Chiayi 621 (China)
2012-11-15
A highly sensitive fiber optic particle plasmon resonance sensor (FO-PPR) is demonstrated for label-free biochemical detection. The sensing strategy relies on interrogating the plasmonic scattering of light from gold nanoparticles on the optical fiber in response to the surrounding refractive index changes or molecular binding events. The refractive index resolution is estimated to be 3.8 x 10{sup -5} RIU. The limit of detection for anti-DNP antibody spiked in buffer is 1.2 x 10{sup -9} g/ml (5.3 pM) by using the DNP-functionalized FO-PPR sensor. The image processing of simultaneously recorded plasmonic scattering photographs at different compartments of the sensor is also demonstrated. Results suggest that the compact sensor can perform multiple independent measurements simultaneously by means of monitoring the plasmonic scattering intensity via photodiodes or a CCD. The potential of using a combination of different kinds of noble metal nanoparticles with different types of functionalized probes in multiple cascaded detection windows on a single fiber to become an inexpensive and ultrasensitive linear-array sensing platform for higher-throughput biochemical detection is provided. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Bremsstrahlung from nuclear scattering at low energy near a resonance. Final report
The understanding of almost all low-energy reaction processes depends upon a distorted wave Born approximation (DWBA) analysis. DWBA procedures, in turn, depend crucially upon a correct optical model description of the projectile-target elastic scattering process. An assumption that the potential is local together with measurements of the elastic scattering data at all energies (0 -infinity) would completely determine that potential, including its off-shell or short-range properties. However, one does not have the luxury of knowing the elastic scattering phase shifts for all energies nor are we so naive as to believe that the potential is completely local. Thus, an alternative approach is called for. The present proposal describes a program to contribute to the general understanding of nuclear reactions by determining as many of the off-shell properties of the proton-nucleus interaction as possible through the study of the proton-nucleus bremsstrahlung process. We seek to establish the limits of validity of a model independent analysis of these reactions in the neighborhood of a resonance or a breakup threshold, and to utilize the differences between this analysis and the data to elucidate those off-shell constraints which any valid proton-nucleus model interaction must satisfy. The bremsstrahlung process provides a method for determining the off-shell properties of the proton-nucleus potential, and the Brooklyn College program offers a unique opportunity to measure these crucial aspects of the low energy proton-nucleus interaction. 18 references
Neutrino neutral current reactions in 12C
Parthasarathy, R.; Yesudian, Premkumar
1985-05-01
The differential and total cross sections for the nuclear reaction ν μ + 12C (g.s) → 12C ∗ (1 +; T = 1, 15.1 MeV) + νμ are investigated for values of 50 ≤ Eνμ ≤ 300 MeV. An effective Hamiltonian for the above nuclear reaction is constructed from the neutrino-quark neutral current weak interaction, by first constructing the neutrino-nucleon neutral current interaction and then using the impulse approximation along with the non-relativistic reduction procedure. The Weinberg-Salam model is the basis of the calculations. Detailed expressions for the differential cross sections are derived including the nucleon momentum-dependent terms. The numerical results are obtained using the general 1 p-shell wavefunctions of Cohen and Kurath. The sensitivity of the total cross sections to the nuclear models and to the Weinberg angle is studied. The corresponding anti-neutrino reaction is also investigated. The ratio R = (σ Tν μ - σ Toverlineνμ) /(σ Tν μ + σ Toverlineνμ) is found to be independent of the nuclear wavefunctions but very sensitive to the Weinberg angle. Thus this observable can be used to determine the free parameter θw in a nuclear reaction, thereby complementing the studies involving free nucleons. The recoil polarization of the final nucleus 12C ∗(1 +; T = 1, 15.1 MeV) is also studied and its importance is pointed out.
SUPERNOVA RESONANCE-SCATTERING LINE PROFILES IN THE ABSENCE OF A PHOTOSPHERE
In supernova (SN) spectroscopy relatively little attention has been given to the properties of optically thick spectral lines in epochs following the photosphere's recession. Most treatments and analyses of post-photospheric optical spectra of SNe assume that forbidden-line emission comprises most if not all spectral features. However, evidence exists that suggests that some spectra exhibit line profiles formed via optically thick resonance-scattering even months or years after the SN explosion. To explore this possibility, we present a geometrical approach to SN spectrum formation based on the 'Elementary Supernova' model, wherein we investigate the characteristics of resonance-scattering in optically thick lines while replacing the photosphere with a transparent central core emitting non-blackbody continuum radiation, akin to the optical continuum provided by decaying 56Co formed during the explosion. We develop the mathematical framework necessary for solving the radiative transfer equation under these conditions and calculate spectra for both isolated and blended lines. Our comparisons with analogous results from the Elementary Supernova code SYNOW reveal several marked differences in line formation. Most notably, resonance lines in these conditions form P Cygni-like profiles, but the emission peaks and absorption troughs shift redward and blueward, respectively, from the line's rest wavelength by a significant amount, despite the spherically symmetric distribution of the line optical depth in the ejecta. These properties and others that we find in this work could lead to misidentification of lines or misattribution of properties of line-forming material at post-photospheric times in SN optical spectra.
Resonant Raman x-ray scattering at the S 2p edge of iron pyrite
The x-ray absorption and resonant inelastic x-ray spectra of iron pyrite (FeS2) have been measured at the S 2p edge and compared with published electronic structure calculations. A minimum in the x-ray absorption intensity interpreted as indicating a gap in the unoccupied density of states is found from about 4 to 6 eV above the bottom of the conduction band, in agreement with some recent calculations. Resonant Raman scattering conditions were set up at the onset of S 2p3/2 absorption and a constant energy loss peak at 1.9 eV was observed. This is assigned to transitions from occupied tg to unoccupied eg states, both of which are predominantly of Fe 3d character but hybridized with the S valence states. This demonstrates that Fe dd excitations can be probed via S 2p resonant spectroscopy, as has been done recently at the O 1s edge for oxide materials
Gold split-ring resonators (SRRs) as substrates for surface-enhanced raman scattering
Yue, Weisheng
2013-10-24
We used gold split ring resonators (SRRs) as substrates for surface-enhanced Raman scattering (SERS). The arrays of SRRs were fabricated by electron-beam lithography in combination with plasma etching. In the detection of rhodamine 6G (R6G) molecules, SERS enhancement factors of the order of 105 was achieved. This SERS enhancement increased as the size of the split gap decrease as a consequence of the matching between the resonance wavelength of the SRRs and the excitation wavelength of SERS. As the size of the split gap decreased, the localized surface plasmon resonance shifted to near the excitation wavelength and, thus, resulted in the increase in the electric field on the nanostructures. We used finite integration method (FIT) to simulate numerically the electromagnetic properties of the SRRs. The results of the simulation agreed well with our experimental observations. We anticipate this work will provide an approach to manipulate the SERS enhancement by modulating the size of split gap with SRRs without affecting the area and structural arrangement. © 2013 American Chemical Society.
Yao, De-Liang; Siemens, D.; Bernard, V.; Epelbaum, E.; Gasparyan, A. M.; Gegelia, J.; Krebs, H.; Meißner, Ulf-G.
2016-05-01
We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the S- and P -partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the D and F waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in order to determine the strangeness content of the nucleon, we calculate the octet baryon masses in the presence of decuplet resonances up to next-to-next-to-leading order in SU(3) baryon chiral perturbation theory. The octet baryon sigma terms are predicted as a byproduct of this calculation.
Transition from resonances to surface waves in pi^+-p elastic scattering
De Micheli, Enrico
2013-01-01
In this article we study resonances and surface waves in $\\pi^+$--p scattering. We focus on the sequence whose spin-parity values are given by $J^p = {3/2}^+,{7/2}^+, {11/2}^+, {15/2}^+,{19/2}^+$. A widely-held belief takes for granted that this sequence can be connected by a moving pole in the complex angular momentum (CAM) plane, which gives rise to a linear trajectory of the form $J = \\alpha_0+\\alpha' m^2$, $\\alpha'\\sim 1/(\\mathrm{GeV})^2$, which is the standard expression of the Regge pole trajectory. But the phenomenology shows that only the first few resonances lie on a trajectory of this type. For higher $J^p$ this rule is violated and is substituted by the relation $J\\sim kR$, where $k$ is the pion--nucleon c.m.s.-momentum, and $R\\sim 1$ fm. In this article we prove: (a) Starting from a non-relativistic model of the proton, regarded as composed by three quarks confined by harmonic potentials, we prove that the first three members of this $\\pi^+$-p resonance sequence can be associated with a vibrationa...
Bhatia, Anand K.
2008-01-01
Applications of the hybrid theory to the scattering of electrons from Ile+ and Li++ and resonances in these systems, A. K. Bhatia, NASA/Goddard Space Flight Center- The Hybrid theory of electron-hydrogen elastic scattering [I] is applied to the S-wave scattering of electrons from He+ and Li++. In this method, both short-range and long-range correlations are included in the Schrodinger equation at the same time. Phase shifts obtained in this calculation have rigorous lower bounds to the exact phase shifts and they are compared with those obtained using the Feshbach projection operator formalism [2], the close-coupling approach [3], and Harris-Nesbet method [4]. The agreement among all the calculations is very good. These systems have doubly-excited or Feshbach resonances embedded in the continuum. The resonance parameters for the lowest ' S resonances in He and Li+ are calculated and they are compared with the results obtained using the Feshbach projection operator formalism [5,6]. It is concluded that accurate resonance parameters can be obtained by the present method, which has the advantage of including corrections due to neighboring resonances and the continuum in which these resonances are embedded.
Cao, Xing; Ni, Binbin; Liang, Jun; Xiang, Zheng; Wang, Qi; Shi, Run; Gu, Xudong; Zhou, Chen; Zhao, Zhengyu; Fu, Song; Liu, Jiang
2016-02-01
This is a companion study to Liang et al. (2014) which reported a "reversed" energy-latitude dispersion pattern of ion precipitation in that the lower energy ion precipitation extends to lower latitudes than the higher-energy ion precipitation. Electromagnetic ion cyclotron (EMIC) waves in the central plasma sheet (CPS) have been suggested to account for this reversed-type ion precipitation. To further investigate the association, we perform a comprehensive study of pitch angle diffusion rates induced by EMIC wave and the resultant proton loss timescales at L = 8-12 around the midnight. Comparing the proton scattering rates in the Earth's dipole field and a more realistic quiet time geomagnetic field constructed from the Tsyganenko 2001 (T01) model, we find that use of a realistic, nondipolar magnetic field model not only decreases the minimum resonant energies of CPS protons but also considerably decreases the limit of strong diffusion and changes the proton pitch angle diffusion rates. Adoption of the T01 model increases EMIC wave diffusion rates at > ~ 60° equatorial pitch angles but decreases them at small equatorial pitch angles. Pitch angle scattering coefficients of 1-10 keV protons due to H+ band EMIC waves can exceed the strong diffusion rate for both geomagnetic field models. While He+ and O+ band EMIC waves can only scatter tens of keV protons efficiently to cause a fully filled loss cone at L > 10, in the T01 magnetic field they can also cause efficient scattering of ~ keV protons in the strong diffusion limit at L > 10. The resultant proton loss timescales by EMIC waves with a nominal amplitude of 0.2 nT vary from a few hours to several days, depending on the wave band and L shell. Overall, the results demonstrate that H+ band EMIC waves, once present, can act as a major contributor to the scattering loss of a few keV protons at lower L shells in the CPS, accounting for the reversed energy-latitude dispersion pattern of proton precipitation at low
Inelastic resonant M-scattering of X-rays from Gd metal with inner-shell excitation
The paper presents results on resonant inner-shell scattering in Gd across the M5 threshold; the scattering channel with formally a 4 p hole in the final state is studied. Two scattering channels are in competition: one at constant transferred energy and another at constant outgoing energy. The branching ratio of the process at constant transferred energy is about 5%. It's isolated the many-body satellite structure of the formally 4p3/2 final hole state and it's discussed the importance of the multiplet splitting and of the super Coster-Kronig conversion of this state into another final state with two 4 d holes. The results with resonant M5 excitation are also compared with those of non-resonant excitation well above the M4 threshold. Guidelines for future research are briefly presented
Carles, R.; Bayle, M.; Benzo, P.; Benassayag, G.; Bonafos, C.; Cacciato, G.; Privitera, V.
2015-11-01
Since the discovery of surface-enhanced Raman scattering (SERS) 40 years ago, the origin of the "background" that is systematically observed in SERS spectra has remained questionable. To deeply analyze this phenomenon, plasmon-resonant Raman scattering was recorded under specific experimental conditions on a panel of composite multilayer samples containing noble metal (Ag and Au) nanoparticles. Stokes, anti-Stokes, and wide, including very low, frequency ranges have been explored. The effects of temperature, size (in the nm range), embedding medium (SiO2, Si3N4, or TiO2) or ligands have been successively analyzed. Both lattice (Lamb modes and bulk phonons) and electron (plasmon mode and electron-hole excitations) dynamics have been investigated. This work confirms that in Ag-based nanoplasmonics composite layers, only Raman scattering by single-particle electronic excitations accounts for the background. This latter appears as an intrinsic phenomenon independently of the presence of molecules on the metallic surface. Its spectral shape is well described by revisiting a model developed in the 1990s for analyzing electron scattering in dirty metals, and used later in superconductors. The gs factor, that determines the effective mean-free path of free carriers, is evaluated, gsexpt=0.33 ±0.04 , in good agreement with a recent evaluation based on time-dependent local density approximation gstheor=0.32 . Confinement and interface roughness effects at the nanometer range thus appear crucial to understand and control SERS enhancement and more generally plasmon-enhanced processes on metallic surfaces.
Discovery of Moessbauer effect in a nuclear transition was a remarkable development. It revealed how long-lived nuclear states with relatively low energies in the kiloelectron volt (keV) region can be excited without recoil. This new effect had a unique feature involving a coupling between nuclear physics and solid-state physics, both in terms of physics and sociology. Physics coupling originates from the fact that recoilless emission and absorption or resonance is only possible if the requirement that nuclei have to be bound in a lattice with quantized vibrational states is fulfilled, and that the finite electron density on the nucleus couples to nuclear degrees of freedom leading to hyperfine interactions. thus, Moessbauer spectroscopy allows peering into solid-state effects using unique nuclear transitions. Sociological aspects of this coupling had been equally startling and fruitful. The interaction between diverse scientific communities, who learned to use Moessbauer spectroscopy proved to be very valuable. For example, biologists, geologists, chemists, physics, materials scientists, and archeologists, all sharing a common spectroscopic technique, also learned to appreciate the beauty and intricacies of each other's fields. As a laboratory-based technique, Moessbauer spectroscopy matured by the end of the 1970s. Further exciting developments took place when accelerator-based techniques were employed, like synchrotron radiation or 'in-beam'Moessbauer experiments with implanted radioactive ions. More recently, two Moessbauer spectrometers on the surface of the Mars kept the technique vibrant and viable up until present time. In this chapter, the authors look into some of the unique aspects of nuclear resonance excited with synchrotron radiation as a probe of condensed matter, including magnetism, valence, vibrations, and lattice dynamics, and review the development of nuclear resonance inelastic x-ray scattering (NRIXS) and synchrotron Moessbauer spectroscopy
Leroy, Valentin; Strybulevych, Anatoliy; Page, John H; Scanlon, Martin G
2011-04-01
We present experimental results on a model system for studying wave propagation in a complex medium exhibiting low-frequency resonances. These experiments enable us to investigate a fundamental question that is relevant for many materials, such as metamaterials, where low-frequency scattering resonances strongly influence the effective medium properties. This question concerns the effect of correlations in the positions of the scatterers on the coupling between their resonances, and hence on wave transport through the medium. To examine this question experimentally, we measure the effective medium wavenumber of acoustic waves in a sample made of bubbles embedded in an elastic matrix over a frequency range that includes the resonance frequency of the bubbles. The effective medium is highly dispersive, showing peaks in the attenuation and the phase velocity as functions of the frequency, which cannot be accurately described using the independent scattering approximation (ISA). This discrepancy may be explained by the effects of the positional correlations of the scatterers, which we show to be dependent on the size of the scatterers. We propose a self-consistent approach for taking this "polydisperse correlation" into account and show that our model better describes the experimental results than the ISA. PMID:21599324
Wang, D; Subedi, R; Deng, X; Ahmed, Z; Allada, K; Aniol, K A; Armstrong, D S; Arrington, J; Bellini, V; Beminiwattha, R; Benesch, J; Benmokhtar, F; Camsonne, A; Canan, M; Cates, G D; Chen, J -P; Chudakov, E; Cisbani, E; Dalton, M M; de Jager, C W; De Leo, R; Deconinck, W; Deur, A; Dutta, C; Fassi, L El; Flay, D; Franklin, G B; Friend, M; Frullani, S; Garibaldi, F; Giusa, A; Glamazdin, A; Golge, S; Grimm, K; Hafidi, K; Hansen, O; Higinbotham, D W; Holmes, R; Holmstrom, T; Holt, R J; Huang, J; Hyde, C E; Jen, C M; Jones, D; Kang, H; King, P; Kowalski, S; Kumar, K S; Lee, J H; LeRose, J J; Liyanage, N; Long, E; McNulty, D; Margaziotis, D J; Meddi, F; Meekins, D G; Mercado, L; Meziani, Z -E; Michaels, R; Mihovilovic, M; Muangma, N; Myers, K E; Nanda, S; Narayan, A; Nelyubin, V; Nuruzzaman,; Oh, Y; Parno, D; Paschke, K D; Phillips, S K; Qian, X; Qiang, Y; Quinn, B; Rakhman, A; Reimer, P E; Rider, K; Riordan, S; Roche, J; Rubin, J; Russo, G; Saenboonruang, K; Saha, A; Sawatzky, B; Shahinyan, A; Silwal, R; Sirca, S; Souder, P A; Suleiman, R; Sulkosky, V; Sutera, C M; Tobias, W A; Waidyawansa, B; Wojtsekhowski, B; Ye, L; Zhao, B; Zheng, X
2013-01-01
We report on parity-violating asymmetries in the nucleon resonance region measured using $5 - 6$ GeV longitudinally polarized electrons scattering off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the $\\Delta(1232)$, and provide a verification of quark-hadron duality in the nucleon electroweak $\\gamma Z$ interference structure functions at the 10-15% level. The results are of particular interest to models relevant for calculating the $\\gamma Z$ box-diagram corrections to elastic parity-violating electron scattering measurements.
Meier, R. R.; Lee, J.-S.
1982-01-01
The transport of resonance radiation under optically thick conditions is shown to be accurately described by a Monte Carlo model of the atomic oxygen 1304 A airglow triplet in which partial frequency redistribution, temperature gradients, pure absorption and multilevel scattering are accounted for. All features of the data can be explained by photoelectron impact excitation and the resonant scattering of sunlight, where the latter source dominates below 100 and above 500 km and is stronger at intermediate altitudes than previously thought. It is concluded that the OI 1304 A emission can be used in studies of excitation processes and atomic oxygen densities in planetary atmospheres.
Lutrus, C.K.; Suck Salk, S.H.
1989-01-01
Resonances for rearrangement collisions (reactive scattering) involving the two dissociative attachment processes, e+HCl..-->..H+Cl/sup -/ and e+H/sub 2/..-->..H+H/sup -/, are examined. It is shown from the Argand-diagram representation of transition amplitudes that strong resonance is present in the former but not in the latter. That is, the strong resonance is evidenced by the clear exhibition of a phase change by ..pi.. in a counterclockwise direction in the Argand diagram as the collision energy increases. Such a manifest phase change is absent in the dissociative attachment process of e+H/sub 2/..-->..H+H/sup -/. This is attributed to the presence of equally strong, direct, and resonant scattering processes, and to the strong influence of mutually destructive interference.
Lutrus, C. K.; Suck Salk, S. H.
1989-01-01
Resonances for rearrangement collisions (reactive scattering) involving the two dissociative attachment processes, e+HCl-->H+Cl- and e+H2-->H+H-, are examined. It is shown from the Argand-diagram representation of transition amplitudes that strong resonance is present in the former but not in the latter. That is, the strong resonance is evidenced by the clear exhibition of a phase change by π in a counterclockwise direction in the Argand diagram as the collision energy increases. Such a manifest phase change is absent in the dissociative attachment process of e+H2-->H+H-. This is attributed to the presence of equally strong, direct, and resonant scattering processes, and to the strong influence of mutually destructive interference.
Resonances in rotationally inelastic scattering of NH{sub 3} and ND{sub 3} with H{sub 2}
Ma, Qianli; Dagdigian, Paul J., E-mail: pjdagdigian@jhu.edu [Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218-2685 (United States); Avoird, Ad van der, E-mail: A.vanderAvoird@theochem.ru.nl; Meerakker, Sebastiaan Y. T. van de [Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Loreau, Jérôme [Service de Chimie Quantique et Photophysique C. P. 160/09, Université Libre de Bruxelles (ULB), 50 Ave. F. D. Roosevelt, 1050 Brussels (Belgium); Alexander, Millard H., E-mail: mha@umd.edu [Department of Chemistry and Biochemistry and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742-2021 (United States)
2015-07-28
We present theoretical studies on the scattering resonances in rotationally inelastic collisions of NH{sub 3} and ND{sub 3} molecules with H{sub 2} molecules. We use the quantum close-coupling method to compute state-to-state integral and differential cross sections for the NH{sub 3}/ND{sub 3}–H{sub 2} system for collision energies between 5 and 70 cm{sup −1}, using a previously reported potential energy surface [Maret et al., Mon. Not. R. Astron. Soc. 399, 425 (2009)]. We identify the resonances as shape or Feshbach resonances. To analyze these, we use an adiabatic bender model, as well as examination at the scattering wave functions and lifetimes. The strength and width of the resonance peaks suggest that they could be observed in a crossed molecular beam experiment involving a Stark-decelerated NH{sub 3} beam.
Vieira, H S
2016-01-01
We study the scattering and the resonant frequencies (quasispectrum) of charged massive scalar waves by Kerr-Newman-Kasuya spacetime (dyon black hole). The equations of motion are written into a Heun form, and its analytical solutions are obtained. We obtain the resonant frequencies expression and the general exact regular partial wave solution. The special cases of the Kerr and Schwarzschild black holes are analyzed and the solutions are shown.
Bakker, Eric J.; Lambert, David L.
1998-11-01
We have made the first detection of circumstellar absorption lines of the 12C13C A 1Πu-X 1Σ+g (Phillips) system 1-0 band and the 12C16O X 1Σ+ first-overtone 2-0 band in the spectrum of the post-AGB star HD 56126 (IRAS 07134+1005). All current detections of circumstellar molecular absorption lines toward HD 56126 (12C2, 12C13C, 12C14N, 13C14N, and 12C16O) yield the same heliocentric velocity of VCSE = 77.6 +/- 0.4 km s-1. The 12C2, 12C13C, and 12C16O lines give rotational temperatures and integrated column densities of Trot = 328 +/- 37 K, log Nint = 15.34 +/- 0.10 cm-2, Trot = 256 +/- 30 K, log Nint = 13.79 +/- 0.12 cm-2, and Trot = 51 +/- 37 K, log Nint = 18.12 +/- 0.13 cm-2, respectively. The rotational temperatures are lower for molecules with a higher permanent dipole moment. Derived relative column densities ratios are 12C2/12C13C = 36 +/- 13 and 12C16O/(12C2 + 12C13C) = 606 +/- 230. Combined with data from a previous paper, we find relative column densities of 12C16O/(12C14N + 13C14N) = 475 +/- 175 and 12C14N/13C14N = 38 +/- 2. Under chemical equilibrium conditions, 12C13C is formed twice as easily as 12C2. The isotopic exchange reaction for 12C2 is too slow to significantly alter the 12C2/12C13C ratio, and the 12C2 to 12C13C ratio is a good measure of half the carbon isotope ratio: 12C/13C = 2 × 12C2/12C13C = 72 +/- 26. This is in agreement with our prediction that the isotopic exchange reaction for 12C14N is efficient and our observation in Paper III of 12C14N/13C14N = 38 +/- 2. A fit of the C2 excitation model of van Dishoeck & Black to the relative population distribution of C2 yields nc σ/I = 3.3 +/- 1.0 × 10-14. At r ~= 1016 cm, this translates into nc = 1.7 × 107 cm-3 and Ṁ~=2.5×10-4 M⊙ yr-1.
Surface-enhanced resonance Raman scattering spectroscopy of single R6G molecules
Zhou Zeng-Hui; Liu Li; Wang Gui-Ying; Xu Zhi-Zhan
2006-01-01
Surface-enhanced resonance Raman scattering (SERRS) of Rhodamine 6G (R6G) adsorbed on colloidal silver clusters has been studied. Based on the great enhancement of the Raman signal and the quench of the fluorescence, the SERRS spectra of R6G were recorded for the samples of dye colloidal solution with different concentrations. Spectral inhomogeneity behaviours from single molecules in the dried sample films were observed with complementary evidences, such as spectral polarization, spectral diffusion, intensity fluctuation of vibrational lines and even "breathing" of the molecules. Sequential spectra observed from a liquid sample with an average of 0.3 dye molecules in the probed volume exhibited the expected Poisson distribution for actually measuring 0, 1 or 2 molecules. Difference between the SERRS spectra of R6G excited by linearly and circularly polarized light were experimentally measured.
Wu, Lihang; Mu, Dan; Gao, Dejiang; Deng, Xinyu; Tian, Yuan; Zhang, Hanqi; Yu, Aimin
2009-02-01
The resonance light scattering (RLS) spectra of bovine serum albumin (BSA)-dithiothreitol (DTT)-sodium dodecylbenzene sulphonate (SDBS) and its analytical application were investigated. The RLS intensity of this system can be effectively enhanced in the presence of BSA. Based on the enhanced RLS intensity, a simple assay for BSA was developed. The experimental results indicate that the enhanced RLS intensity is proportional to the concentration of BSA in the range from 1.0 × 10 -8 to 7.5 × 10 -7 mol L -1 with the determination limit of 5.0 × 10 -9 mol L -1. The effects of pH, concentration of SDBS and DTT on the RLS enhancement were discussed. Most metal ions have little interference on the determination of BSA. Some synthetic and real samples were analyzed, and the results obtained were in good agreement with those obtained by Bradford method.
2008-01-01
It was found that multi-walled carbon nanotubes (MWNTs) could catalyze the redox reaction between chlorauric acid (HAuCl4) and reductive drugs such as tetracycline hydrochloride (TC), producing gold nanoparticles (Au NPs). By measuring the plasmon resonance light scattering (PRLS) signals of the resulting Au NPs, tetracycline hydrochloride can be detected simply and rapidly with a linear range of 4―26 μmol/L, a correlated coefficient (r ) of 0.9955, and a limit of detection (3σ) of 6.0 nmol/L. This method has been successfully applied to the detection of tetracycline hydrochloride tablets in clinic with the recovery of 101.9% and that of fresh urine samples with the recovery of 98.3%―102.0%.
HU Po; HUANG ChengZhi; ZHANG Li
2008-01-01
It was found that multi-walled carbon nanotubes (MWNTs) could catalyze the redox reaction between chlorauric acid (HAuCl4) and reductive drugs such as tetracycline hydrochloride (TC), producing gold nanoparticles (Au NPs). By measuring the plasmon resonance light scattering (PRLS) signals of the resulting Au NPs, tetracycline hydrochloride can be detected simply and rapidly with a linear range of 4-26 μmol/L, a correlated coefficient (r) of 0.9955, and a limit of detection (3σ) of 6.0 nmol/L. This method has been successfully applied to the detection of tetracycline hydrochloride tablets in clinic with the recovery of 101.9% and that of fresh urine samples with the recovery of 96.3%-102.0%.
Zhang, Fang; Zheng, Yonghong; Liang, Jiaman; Long, Sha; Chen, Xianping; Tan, Kejun
2016-04-01
A simple, highly sensitive resonance light scattering (RLS) method for the detection of perfluorooctanoic acid (PFOA) has been developed based on the interaction with crystal violet (CV). It was found that PFOA can form complexes with CV in acid medium resulting in remarkable enhancement of the RLS intensity of the system. And the enhanced RLS intensities are in proportion to the concentration of PFOA in the range of 0.1-25.0 μmol/L (R2 = 0.9998), with a detection limit of 11.0 nmol/L (S/N = 3). In this work, the optimum reaction conditions and the interferences of foreign substances were investigated. The reaction mechanism between CV and PFOA was also studied by the absorption spectrum and scanning electron microscope (SEM). This method is successfully applied to the determination of PFOA in tap water and Jialing river water samples with RSD ≤ 4.04%.
2008-01-01
Silver nanoparticles were prepared under a microwave high-pressure condition using citric acid sodium as a reducer while the excess citrate was removed under high speed centrifugation. There is a resonance scattering (RS) peak at 470 nm for silver nanoparticles. In a pH 4.0 HAc-NaAc buffer solution, hydroxyl radicals from the Fenton reaction can oxidize silver nanoparticles to Ag+, resulting in the RS intensity decreasing. The decreased RS intensity at 470 nm (△I 470 nm) is linear with respect to the concentration of H2O2 (C) in the range of 0.27-7.56 μmol/L with a detection limit of 0.23 μmol/L. Its regression equation is △I 470 nm = 24.3 C + 13.8 with a correlation coefficient of 0.9959. This method was applied to screening the antioxidants with satisfactory results.
We have developed a novel resonance light scattering (RLS) assay for the sensitive and selective determination of iodide. It is based on the use of histidine-stabilized gold nanoclusters (His-AuNCs) which undergo fusion and aggregation in the presence of iodide. The resulting enhancement in the intensity of RLS is proportional to the concentration of iodide in the 0.01 to 8.0 μM range, and the detection limit is as low as 1.8 nM at a signal-to-noise ratio of 3. This “turn-on” method is highly selective for iodide and not interfered by other ions commonly present. It was applied to the determination of iodide in (spiked) real water samples. (author)
Resonance light scattering determination of 6-mercaptopurine coupled with HPLC technique
Li, Ai Ping; Peng, Jing Dong; Zhou, MingQiong; Zhang, Jin
2016-02-01
A simple, fast, costless, sensitive and selective method of resonance light scattering coupled with HPLC was established for the determination of 6-mercaptopurine in human urine sample. In a Britton-Robinson buffer solution of pH 5.5, the formation of coordination complex between 6-mercaptopurine and metal palladium (II) led to enhance the RLS intensity of the system. The RLS signal was detected by fluorescence detector at λex = λem = 315 nm. The analytical parameters were provided by the coupled system, the linear of 6-mercaptopurine response from 0.0615 to 2.40 μg L- 1 and the limit of detection (S/N = 3) was 0.05 μg L- 1. The presented method has been applied to determine 6-mercaptopurine in human urine samples which obtained satisfactory results. Moreover, the reaction mechanism and possible reasons for enhancement of RLS were fully discussed.
Hu, Qing (Inventor); Williams, Benjamin S. (Inventor)
2009-01-01
The present invention provides quantum cascade lasers and amplifier that operate in a frequency range of about 1 Terahertz to about 10 Terahertz. In one aspect, a quantum cascade laser of the invention includes a semiconductor heterostructure that provides a plurality of lasing modules connected in series. Each lasing module includes a plurality of quantum well structure that collectively generate at least an upper lasing state, a lower lasing state, and a relaxation state such that the upper and the lower lasing states are separated by an energy corresponding to an optical frequency in a range of about 1 to about 10 Terahertz. The lower lasing state is selectively depopulated via resonant LO-phonon scattering of electrons into the relaxation state.
Jost function description of near threshold resonances for coupled-channel scattering
Simbotin, I
2015-01-01
We study the effect of resonances near the threshold of low energy ($\\varepsilon$) reactive scattering processes, and find an anomalous behavior of the $s$-wave cross sections. For reaction and inelastic processes, the cross section exhibits the energy dependence $\\sigma\\sim\\varepsilon^{-3/2}$ instead of the standard Wigner's law threshold behavior $\\sigma\\sim\\varepsilon^{-1/2}$. Wigner's law is still valid as $\\varepsilon\\rightarrow 0$, but in a narrow range of energies. We illustrate these effects with two reactive systems, a low-reactive system (H$_2$ + Cl) and a more reactive one (H$_2$ + F). We provide analytical expressions, and explain this anomalous behavior using the properties of the Jost functions. We also discuss the implication of the reaction rate coefficients behaving as $K\\sim 1/T$ at low temperatures, instead of the expected constant rate of the Wigner regime in ultracold physics and chemistry.
Jost function description of near threshold resonances for coupled-channel scattering
Simbotin, I.; Côté, R.
2015-11-01
We study the effect of resonances near the threshold of low energy (ε) reactive scattering processes, and find an anomalous behavior of the s-wave cross sections. For reaction and inelastic processes, the cross section exhibits the energy dependence σ ∼ε - 3 / 2 instead of the standard Wigner's law threshold behavior σ ∼ε - 1 / 2 . Wigner's law is still valid as ε → 0 , but in a narrow range of energies. We illustrate these effects with two reactive systems, a low-reactive system (H2 + Cl) and a more reactive one (H2 + F). We provide analytical expressions, and explain this anomalous behavior using the properties of the Jost functions. We also discuss the implication of the reaction rate coefficients behaving as K ∼ 1 / T at low temperatures, instead of the expected constant rate of the Wigner regime in ultracold physics and chemistry.
Bairamov, B. Kh.
2016-04-01
This paper reports on the formation of complexes consisting of isolated free-standing crystalline semiconductor quantum dots, for example, nc-Si/SiO2, functionalized by short oligonucleotides, for example, the single-stranded system d(20G, 20T). Here, d are deoxyribonucleotides, G and T are guanine and thymine nucleotides, respectively. It has been found that these complexes are unique objects for the elucidation of the specific features in the manifestation of new quantum-size effects in biomacromolecules. It has been demonstrated that the possibility exists of detecting and recording, in such complexes of biomacromolecules, spectrally selective resonance enhancement of Raman scattering intensity in fluctuations of nucleotide molecules due to coherent nonradiative transfer of a photoexcited electron and a hole at the interface of the complex. This dynamic optical imaging of spectral responses can be of applied interest for the development of nanobiophotonic technologies.
High-resolution neutron transmission, capture and differential elastic scattering measurements have been made for 58Ni-enriched targets at the Oak Ridge Electron Linear Accelerator (ORELA) from the eV to the MeV region. The three sets of data were analyzed simultaneously from 10 to 450 keV, and the transmission analysis was extended to 650 keV. For the 52 s-wave resonances observed between 10 and 650 keV, the average level spacing, D0, and the strength function, S0, are 12.2 +- 1.0 keV and (3.1 +- 0.6) x 10-4, respectively
The optical/ultraviolet excess of isolated neutron stars in the resonant cyclotron scattering model
Hao Tong; Ren-Xin Xu; Li-Ming Song
2011-01-01
X-ray dim isolated neutron stars are peculiar pulsar-like objects,characterized by their Planck-like spectrum.In studying their spectral energy distributions,optical/ultraviolet (UV) excess is a long standing problem.Recently Kaplan et al.measured the optical/UV excess for all seven sources,which is understandable in the resonant cyclotron scattering (RCS) model previously addressed.The RCS model calculations show that the RCS process can account for the observed optical/UV excess for most sources.The flat spectrum of RX J2143.0+0654 may be due to contributions from the bremsstrahlung emission of the electron system in addition to the RCS process.
Wang, Yu; Bi, Shuyun; Zhou, Huifeng; Zhao, Tingting
2015-07-01
A new method for the determination of calf thymus DNA at nanogram level was proposed based on the enhanced resonance light scattering (RLS) signals of DNA in the presence of procyanidin and cetylpyridinium bromide dihydrate (CPB). Under the experimental conditions, the RLS intensity of DNA at 291.0 nm was greatly enhanced by procyanidin-CPB at pH 7.0. There was a good linear relationship (r = 0.9993) between the enhanced RLS intensity (ΔIRLS) and DNA concentration of 0.0084-3.36 μg mL-1. The limit of detection (LOD) was 2.27 ng mL-1 (3S0/S). Three synthetic DNA samples were measured with satisfactory, and the recovery was 102.3-107.2%.
Non-Fermi Liquid Behavior Induced by Resonant Diquark-pair Scattering in Heated Quark Matter
Kitazawa, M; Nemoto, Y; Kitazawa, Masakiyo; Kunihiro, Teiji; Nemoto, Yukio
2005-01-01
We show how the quasiparticle picture of quarks changes near but above the critical temperature T_c of the color-superconducting phase transition in the heated quark matter. We demonstrate that a non-Fermi liquid behavior of the matter develops drastically when the diquark coupling constant is increased owing to the coupling of the quark with the pairing soft mode: We clarify that the depression and eventually the appearance of a gap structure in the spectral function as well as the anomalous quark dispersion relation of the quark can be understood in terms of the resonant scattering between the incident quark and a particle near the Fermi surface to make the pairing soft mode.
Isoscalar $\\pi\\pi$ scattering and the $\\sigma$ meson resonance from QCD
Briceno, Raul A; Edwards, Robert G; Wilson, David J
2016-01-01
We present for the first time a determination of the energy dependence of the isoscalar $\\pi\\pi$ elastic scattering phase-shift within a first-principles numerical lattice approach to QCD. Hadronic correlation functions are computed including all required quark propagation diagrams, and from these the discrete spectrum of states in the finite volume defined by the lattice boundary is extracted. From the volume dependence of the spectrum we obtain the $S$-wave phase-shift up to the $K\\overline{K}$ threshold. Calculations are performed at two values of the $u,d$ quark mass corresponding to $m_\\pi = 236, 391$ MeV and the resulting amplitudes are described in terms of a $\\sigma$ meson which evolves from a bound-state below $\\pi\\pi$ threshold at the heavier quark mass, to a broad resonance at the lighter quark mass.
Resonant x-ray scattering study of layered TbBaCo2O5.5
Blasco, J.; García, J.; Subías, G.; Renevier, H.; Stingaciu, M.; Conder, K.; Herrero-Martín, J.
2008-08-01
Resonant x-ray scattering (RXS) experiments have been performed at the Co K edge in the TbBaCo2O5.5 sample. Linear scans in the reciprocal space along [0k0] and [h00] directions were carried out at different energies between 350 and 90 K. This temperature range probes the metallic, insulating, ferrimagnetic, and antiferromagnetic phases. No new reflections, either resonant or not, were detected in any phase transition. We have found strong resonances close to the absorption edge energy for (0k0) reflections with k odd. These resonances remain almost constant for the different phases. The cusp of the resonant scattering is either up—(0 3 0) and (0 7 0)—or down—(0 1 0) and (0 5 0)—depending on the k value, and this behavior was completely explained in the frame of the crystal structure and the atomic position of the Tb and Ba atoms. The occurrence of the resonant scattering and its azimuthal behavior has been explained in terms of the anisotropy of the tensor of susceptibility (ATS reflections). RXS comes from the presence of two different environments for the Co ions, octahedra and pyramids of oxygens, ordered along the b axis. No evidence for further contributions, such as an orbital ordering, has been found in these experiments in the insulating low temperature phase.
Investigation of the P-odd asymmetry in the resonance scattering of neutron capture gamma-rays
The PCN-Asymmetry of the resonance scattering of circularly polarized neutron capture gamma-rays was investigated for the following nuclei as scatterers: 112Cd, 118Sn, 139La, 141Pr, 142Nd, 205Tl and 208Pb. The experiments were carried out on the polarized neutron beam of the Institut Laue Langevin's High Flux Reactor. For six nuclei-scatterer combinations limits on the value of the PNC-asymmetry of the order 10-4 to 10-3 were obtained. For 205Tl a PNC-asymmetry of a=(+ 4.8 ± 1.5).10-5 was observed
Development of 119Sn nuclear resonance scattering of synchrotron radiation and first applications
In the framework of this thesis the NRS technique has been developed and applied, for the first time at the European Synchrotron Radiation Facility, at the resonance of 119Sn. Elastic nuclear forward scattering (NFS) is ideal for studies of hyperfine interactions, where information about the electronic and magnetic properties of solids is obtained. On the other hand nuclear inelastic scattering (NIS) allows one to study the phonon density of states (DOS) of Moessbauer isotopes in various kinds of systems. In the first stage, technical developments have been made, particularly with regards the used optical elements. A key point has been the construction of a high resolution monochromator (HRM) for the resonance of 119Sn, with an energy resolution of about 0.65 meV, perfectly suited to perform NIS experiments. A second HRM optimised in throughput has been constructed and used, in combination with focussing elements (bent crystals and compound refractive lenses), to perform NFS experiments at very high pressure. For the first applications of 119Sn NIS, the phonon DOS of β-Sn has been directly determined from the NIS spectra measured at T = 100 K and T = 300 K. An excellent agreement has been found with the phonon DOS obtained theoretically by previous calculations. Moreover, dynamical and thermodynamical properties of β-Sn extracted from the determined DOS, such as the Lamb-Moessbauer factor and the specific heat, are found to be in good agreement with previously published results. As a first application of 119Sn NFS experiments at high pressure, the system U(In1-xSnx)3 has been chosen. (orig.)
Leutenegger, Maurice A.; Owocki, Stanley P.; Kahn, Steven M.; Paerels, Frits B. S.
2006-01-01
We fit the Doppler profiles of the He-like triplet complexes of \\ion{O}{7} and \\ion{N}{6} in the X-ray spectrum of the O star $\\zeta$ Puppis, using XMM-Newton RGS data collected over $\\sim 400$ ks of exposure. We find that they cannot be well fit if the resonance and intercombination lines are constrained to have the same profile shape. However, a significantly better fit is achieved with a model incorporating the effects of resonance scattering, which causes the resonance line to become more...
The resonant coherent interaction of an ion with an oriented crystal surface, under grazing-incidence conditions with respect to a special direction of the crystal, gives rise to electron loss to the continuum from electronic bound states of the ion. The calculations presented below predict large probabilities for electron emission due to this mechanism. The electrons are emitted with well defined energies, expressed in terms of the condition of resonance. Furthermore, the emission takes place around certain preferential directions, which are determined by both the latter condition and the symmetry of the surface lattice. Our calculations for MeV He+ ions scattered at a W(001) surface along the left-angle 100 right-angle direction with glancing angle of 0--2 mrad indicate a yield of emission close to 1. Using heavier projectiles, one obtains smaller yields, but still large enough to be measurable in some cases (e.g., ∼0.9 for 53 MeV B4+ and an angle of incidence of 1 mrad). Besides, the initial bound state is energy shifted due to the interaction with both the crystal potential and the velocity-dependent image potential. This results in a slight shift of the peaks of emission, which suggests a possible spectroscopy for analyzing the dynamical interaction of electronic bound states with solid surfaces
Garcia de Abajo, F.J. (Departamento de Ciencias de la Computacion e Inteligencia Artificial, Facultad de Informatica, Universidad del Pais Vasco, Apartado 649, 20080 San Sebastian (Spain)); Ponce, V.H.; Echenique, P.M. (Departamento de Fisica de Materiales, Facultad de Quimica, Universidad del Pais Vasco, Apartado 1072, 20080 San Sebastian (Spain))
1994-01-15
The resonant coherent interaction of an ion with an oriented crystal surface, under grazing-incidence conditions with respect to a special direction of the crystal, gives rise to electron loss to the continuum from electronic bound states of the ion. The calculations presented below predict large probabilities for electron emission due to this mechanism. The electrons are emitted with well defined energies, expressed in terms of the condition of resonance. Furthermore, the emission takes place around certain preferential directions, which are determined by both the latter condition and the symmetry of the surface lattice. Our calculations for MeV He[sup +] ions scattered at a W(001) surface along the [l angle]100[r angle] direction with glancing angle of 0--2 mrad indicate a yield of emission close to 1. Using heavier projectiles, one obtains smaller yields, but still large enough to be measurable in some cases (e.g., [approx]0.9 for 53 MeV B[sup 4+] and an angle of incidence of 1 mrad). Besides, the initial bound state is energy shifted due to the interaction with both the crystal potential and the velocity-dependent image potential. This results in a slight shift of the peaks of emission, which suggests a possible spectroscopy for analyzing the dynamical interaction of electronic bound states with solid surfaces.
Evidence for a New Resonance from Polarized Neutron-Proton Scattering
Adlarson, P; Bardan, W; Bashkanov, M; Bergmann, F S; Berlowski, M; Bhatt, H; Buescher, M; Ciepa, H Calen I; Clement, H; Coderre, D; Czerwinski, E; Demmich, K; Doroshkevich, E; Engels, R; Erven, A; Erven, W; Eyrich, W; Fedorets, P; Foehl, K; Fransson, K; Goldenbaum, F; Goslawski, P; Goswami, A; Grigoyev, K; Gullstroem, C -O; Hauenstein, F; Heijkenskjoeld, L; Hejny, V; Hodana, M; Hoistad, B; Huesken, N; Jany, A; Jany, B R; Jarczyk, L; Johansson, T; Kamys, B; Kemmerling, G; Khan, F A; Khoukaz, A; Kirrilov, D A; Kistryn, S; Kleines, H; Klos, B; Krapp, M; Krzemien, W; Kulessa, P; Kupsc, A; Lalwani, K; Lersch, D; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Marianski, B; Mikirtychiants, M; Morsch, H -P; Moskal, P; Ohm, H; Ozerianska, I; del Rio, E Perez; Piskunov, N M; Podkopal, P; Prasuhn, D; Pricking, A; Pszczel, D; Pysz, K; Pysniak, A; Redmer, C F; Ritman, J; Roy, A; Rudy, Z; Sawant, S; Schadmand, S; Sefzick, T; Serdyuk, V; Siudak, R; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Stephan, E; Sterzenbach, G; Stockhorst, H; Stroeher, H; Szczurek, A; Taeschner, A; Trzcinski, A; Varma, R; Wagner, G J; Wolke, M; Wronska, A; Wuestner, P; Wurm, P; Yamamoto, A; Yurev, L; Zabierowski, J; Zielinski, M J; Zink, A; Zlomanczuk, J; Zupranski, P; Zurek, M; Workman, R L; Briscoe, W J; Strakovsky, I I
2014-01-01
Exclusive and kinematically complete high-statistics measurements of quasifree polarized $\\vec{n}p$ scattering have been performed in the energy region of the narrow resonance structure $d^*$ with $I(J^P) = 0(3^+)$, $M~\\approx$~2380~MeV/$c^2$ and $\\Gamma \\approx$ 70 MeV observed recently in the double-pionic fusion channels $pn \\to d\\pi^0\\pi^0$ and $pn \\to d\\pi^+\\pi^-$. The experiment was carried out with the WASA detector setup at COSY having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process $\\vec{d}p \\to np + p_{spectator}$. That way the $np$ analyzing power $A_y$ was measured over a large angular range. The obtained $A_y$ angular distributions deviate systematically from the current SAID SP07 NN partial-wave solution. Incorporating the new $A_y$ data into the SAID analysis produces a pole in the $^3D_3 - ^3G_3$ waves as expected from the $d^*$ resonance hypothesis.
Yao, De-Liang; Bernard, V; Epelbaum, E; Gasparyan, A M; Gegelia, J; Krebs, H; Meißner, Ulf-G
2016-01-01
We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the $S$- and $P$-partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the $D$ and $F$ waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in ...
Structure of the Hoyle State in 12C
The first excited 0+ state in 12C (Hoyle state) has been predicted to be a dilute self-bound gas of bosonic α particles, similar to a Bose-Einstein condensate. To clarify this conjecture, precise electron scattering data on form factors of the ground state and the transition to the Hoyle state are compared with results of the fermionic molecular dynamics model, a microscopic α-cluster model, and an α-cluster model with reduced degrees of freedom (in the spirit of a Bose-Einstein condensed state). The data indicate clearly a dilute density with a large spatial extension of the Hoyle state. A closer inspection of the model calculations, which reproduce the experimental findings, reveals that the term Bose-Einstein condensation of three α particles must not be taken too literally
Schnitzer, Cheryl S.; Reim, Candace Lawson; Sirois, John J.; House, Paul G.
2010-01-01
Advanced chemistry students are introduced to surface-enhanced resonance Raman scattering (SERRS) by studying how sodium copper chlorophyllin (CuChl) adsorbs onto silver colloids (CuChl/Ag) as a function of pH. Using both SERRS and visible extinction spectroscopy, the extent of CuChl adsorption and colloidal aggregation are monitored. Initially at…
Band structure effects in nitrogen K-edge resonant inelastic X ray scattering from GaN
Strocov, V. N.; Schmitt, T.; Rubensson, J.-E.; Blaha, P; Paskova, T.; Nilsson, P. O.
2004-01-01
Systematic experimental data on resonant inelastic X-ray scattering (RIXS) in GaN near the N K-edge are presented for the first time. Excitation energy dependence of the spectral structures manifests the band structure effects originating from momentum selectivity of the RIXS process. This finding allows obtaining k-resolved band structure information for GaN crystals and nanostructures.