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Sample records for giant dipole resonance

  1. Giant dipole resonance in hot nuclei

    International Nuclear Information System (INIS)

    Mau, N.V.

    1993-01-01

    Giant resonances built on an excited state of the nucleus at a finite temperature T are studied. The following questions are investigated: how long such collective effects occur in a nucleus when T increases. How the properties of the giant resonances vary when the temperature increases. How the study of giant resonances in hot nuclei can give information on the structure of the nucleus in a highly excited state. The special case of the giant dipole resonance is studied. Some of the experimental results are reviewed and in their theoretical interpretation is discussed. (K.A.). 56 refs., 20 figs., 4 tabs

  2. Giant dipole resonance by many levels theory

    International Nuclear Information System (INIS)

    Mondaini, R.P.

    1977-01-01

    The many levels theory is applied to photonuclear effect, in particular, in giant dipole resonance. A review about photonuclear dipole absorption, comparing with atomic case is done. The derivation of sum rules; their modifications by introduction of the concepts of effective charges and mass and the Siegert theorem. The experimental distributions are compared with results obtained by curve adjustment. (M.C.K.) [pt

  3. Giant dipole resonances built on excited states

    International Nuclear Information System (INIS)

    Snover, K.A.

    1983-01-01

    The properties of giant dipole resonances built on excited nuclear states are reviewed, with emphasis on recent results. Nonstatistical (p,γ) reactions in light nuclei, and statistical complex-particle reactions in light and heavy nuclei are discussed. 27 references

  4. Stability of the giant dipole resonance

    International Nuclear Information System (INIS)

    Espino, J.M.; Gallardo, M.

    1987-01-01

    The Giant Dipole Resonance (GDR), because of its stability and its typical period of vibration, can be used as a test for compound nucleus reactions at high temperatures. This stability is studied in a simple model up to 6 MeV of temperature. The experimental methods for getting the properties of the GDR at T ≠ 0 are also commented. (author)

  5. Photon scattering by the giant dipole resonance

    International Nuclear Information System (INIS)

    Bowles, T.J.; Holt, R.J.; Jackson, H.E.; McKeown, R.D.; Specht, J.R.

    1979-01-01

    Although many features of the giant dipole resonance are well known, the coupling between the basic dipole oscillation and other nuclear collective degrees of freedom such as surface vibrations and rotations is poorly understood. This aspect was investigated by elastic and inelastic bremsstrahlung scattering of tagged photons over the energy range 15 to 22 MeV. Target nuclei were 60 Ni, 52 Cr, 56 Fe, 92 Mo, and 96 Mo. Scattering and absorption cross sections are tabulated, along with parameters obtained from a two-Lorentzian analysis of the scattering cross sections; measured spectra are shown. It was necessary to remove Thomson scattering from the experimental results. It was found that coupling to surface vibrations in the giant dipole resonance is much weaker than the dynamic collective model suggests. The elastic scattering cross section for all targets but 60 Ni showed structure that is not evident in the absorption cross section measurement. 12 figures, 2 tables

  6. High temperature giant dipole and isoscalar resonances

    International Nuclear Information System (INIS)

    Navarro, J.; Barranco, M.; Garcias, F.; Suraud, E.

    1990-01-01

    We present a systematic study of the Giant Dipole Resonance (GDR) at high temperatures (T > ∼ 4 MeV) in the framework of a semi-classical approximation that uses the m 1 and m 3 RPA sum rules to estimate the GDR mean energy. We focus on the evolution with T of the collective nature of the GDR and of the L = 0,2,3 and 4 isoscalar resonances. We find that the GDR remains particularly collective at high T, suggesting that it might be possible to observe it experimentally even at temperatures close to the maximum one a nucleus can sustain

  7. Temperature dependence of giant dipole resonance width

    International Nuclear Information System (INIS)

    Vdovin, A.I.; Storozhenko, A.N.

    2005-01-01

    The quasiparticle-phonon nuclear model extended to finite temperature within the framework of the thermo field dynamics is applied to calculate a temperature dependence of the spreading width Γ d own of a giant dipole resonance. Numerical calculations are made for 12S n and 208 Pb nuclei. It is found that the width Γ d own increases with T. The reason of this effect is discussed as well as a relation of the present approach to other ones existing in the literature

  8. Collective Hamiltonians for dipole giant resonances

    International Nuclear Information System (INIS)

    Weiss, L.I.

    1991-07-01

    The collective hamiltonian for the Giant Dipole resonance (GDR), in the Goldhaber-Teller-Model, is analytically constructed using the semiclassical and generator coordinates method. Initially a conveniently parametrized set of many body wave functions and a microscopic hamiltonian, the Skyrme hamiltonian - are used. These collective Hamiltonians are applied to the investigation of the GDR, in He 4 , O 16 and Ca 40 nuclei. Also the energies and spectra of the GDR are obtained in these nuclei. The two sets of results are compared, and the zero point energy effects analysed. (author)

  9. Giant dipole resonance in hot rotating nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarty, D.R. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India); Dinh Dang, N. [RIKEN, Nishina Centre for Accelerator-based Science, Saitama (Japan); VINATOM, Institute of Nuclear Science and Technique, Hanoi (Viet Nam); Datar, V.M. [Tata Institute of Fundamental Research, INO Cell, Mumbai (India)

    2016-05-15

    Over the last several decades, extensive experimental and theoretical work has been done on the giant dipole resonance (GDR) in excited nuclei covering a wide range of temperature (T), angular momentum (J) and nuclear mass. A reasonable stability of the GDR centroid energy and an increase of the GDR width with T (in the range∝1-3 MeV) and J are the two well-established results. Some experiments have indicated the saturation of the GDR width at high T. The gradual disappearance of the GDR vibration at much higher T has been observed. Experiments on the Jacobi transition and the GDR built on superdeformed shapes at high rotational frequencies have been reported in a few cases. Theoretical calculations on the damping of the collective dipole vibration, characterised by the GDR width, have been carried out within various models such as the thermal shape fluctuation model and the phonon damping model. These models offer different interpretations of the variation of the GDR width with T and J and have met with varying degrees of success in explaining the experimental data. In this review, the present experimental and theoretical status in this field is discussed along with the future outlook. The interesting phenomenon of the pre-equilibrium GDR excitation in nuclear reactions is briefly addressed. (orig.)

  10. Fragmentation of giant dipole resonance at finite temperature

    International Nuclear Information System (INIS)

    Vdovin, A.

    2005-01-01

    It is well known that the main part of a width of a collective giant resonance built on the ground state in heavy nuclei is due to coupling of one-phonon vibrational states with more complex ones like two phonon or two-particle - two-hole. So it seems natural that the same idea was also explored in studying of the formation and dependence on temperature of a width of giant resonances built on a compound nuclear state. The first microscopic calculations of a giant dipole resonance width at finite temperature have demonstrated its weak dependence on T whereas the experimental width Γ exp strongly increases up to T≤3 MeV. The observed thermal behaviour of Γ exp was attributed mainly to thermal fluctuations of a nuclear shape at finite T . However, further theoretical studies of the problem have shown a strengthening of the GDR spreading with T. We calculate a fragmentation of the giant dipole resonance in hot spherical nuclei within the approach based on the quasiparticle-phonon model extended to finite temperature in with the formalism of thermofield dynamics. The fragmentation of collective giant dipole vibrations at finite T is due to the coupling with 'two-thermal phonon' configurations. The energies and structures of thermal phonon states are calculated from the thermal RPA temperature dependence of the variance σ th of a theoretical E1 strength function and the experimental GDR width Γ exp in 120 Sn. The coupling of thermal phonons is determined by their fermionic structure. The variance σ th of the E1 strength function is found continuously increasing with temperature. The main reason of this behavior is the coupling of the dipole phonons with very low-lying particle-particle (hole-hole) thermal phonons. These phonons are noncollective ones and they appear only at T≠0. The calculated T dependence of σ th is quite similar to that of the experimental width Γ exp in 120 Sn and 208 Pb

  11. The width of the giant dipole resonance at finite temperature

    International Nuclear Information System (INIS)

    Mau, N.V.

    1992-01-01

    A method is proposed to evaluate the effect of the change of the Fermi sea on the width of the giant dipole resonance at finite temperature. In a schematic model it is found that, indeed, in 208 Pb the width increases very sharply up to about T=4 MeV but shows a much weaker variation for higher temperature. (author) 26 refs., 7 figs., 2 tabs

  12. Temperature dependence of spreading width of giant dipole resonance

    International Nuclear Information System (INIS)

    Storozhenko, A.N.; Vdovin, A.I.; Ventura, A.; Blokhin, A.I.

    2002-01-01

    The Quasiparticle-Phonon Nuclear Model extended to finite temperature within the framework of Thermo Field Dynamics is applied to calculate a temperature dependence of the spreading width Γ ↓ of a giant dipole resonance. Numerical calculations are made for 120 Sn and 208 Pb nuclei. It is found that Γ ↓ increases with T. The reason of this effect is discussed as well as a relation of the present approach to other ones, existing in the literature

  13. The natural line shape of the giant dipole resonance

    International Nuclear Information System (INIS)

    Gordon, E.F.; Pitthan, R.

    1977-01-01

    Investigation of photoabsorption experiments in the spherical nucleus 141 Pr, the quasispherical dynamically deformed 197 Au, and the statically deformed 165 Ho showed that the function which describes best the energy dependence of the reduced transition probability is given by the Breit-Wigner form rather than the Lorentz form. However, the form of the resulting measured cross section is approximately of the Lorentz type. The dependence of the giant resonance width GAMMA on the excitation energy was also investigated, and found to be less than 1% per MeV if one considered the known isovector E2 resonance above the giant dipole resonance. Best fit values of the reduced transition probabilities for the three nuclei are given and compared to (e,e') results. (Auth.)

  14. Electromagnetic excitation of the two-phonon giant dipole resonance

    International Nuclear Information System (INIS)

    Emling, H.

    1994-03-01

    It is the aim of this article to summarize our present knowledge on the double isovector giant dipole resonance (DGDR) and our understanding of the electromagnetic excitation mechanism in heavy ion collisions in the relativistic energy regime. In the following chapter, a brief resume on the history of giant resonances is given and, based on their understanding, conclusions on the expected properties of multi-phonon resonances are drawn. In chapter 2, the essential features of electromagnetic heavy ion interactions at (near) relativistic velocities will be illuminated and the theoretical framework is presented, which describes such processes. New experimental methods were required for an appropriate study of Coulomb dissociation processes, which are discussed in chapter 3 together with the experimental results. Chapter 4 is dedicated to summarize the results from electromagnetic excitation studies, to compare with those from alternative methods and, in particular, to contrast experimental findings with theoretical predictions and to address open problems. (orig.)

  15. The isoscalar giant dipole resonance and nuclear incompressibility

    International Nuclear Information System (INIS)

    Garg, U.

    2000-01-01

    Complete text of publication follows. The current status of the experimental work on the ISOSCALAR giant dipole resonance (ISGDR) will be reviewed. ISGDR is an exotic mode of collective nuclear vibration and can be described as a hydrodynamical density oscillation in which the volume of the nucleus remains constant and the state can be visualized in the form of a compression wave-analogous to a sound wave-oscillating back and forth through the nucleus. [1] Convincing evidence for the ISGDR has now been obtained in inelastic α-scattering measurements at 200 MeV (IUCF) [2], 240 MeV (Texas A and M) [3] and 400 MeV (RCNP, Osaka) [4]. In all nuclei studied so far, the ISGDR strength is observed to be spread over a rather wide excitation-energy range (up to ∼ 15 MeV). The excitation energy of the ISGDR is related to the nuclear incompressibility, K ∞ . The ISGDR results so far point to a value for K ∞ that is ∼ 30-40% lower than the obtained from the energies of the other compressional mode, the giant monopole resonance. Results from recent theoretical attempts to reconcile this difference will be presented. This work has been supported in part by the U.S. National Science Foundation. (author)

  16. Influence of complex particle emission on properties of giant dipole resonance of hot nuclei

    International Nuclear Information System (INIS)

    Wen Wanxin; Jin Genming

    2003-01-01

    The possible reasons for the discrepancy between calculation results based on the statistical evaporation model and experimental data of giant dipole resonance of very hot nuclei are discussed. Both of simulations with the standard CASCADE code and the code coupling complex particle emission are carried out. It is shown that the complex particle emission affects the properties of giant dipole resonance of very hot nuclei

  17. Is There a Pronounced Giant Dipole Resonance in 4He?

    International Nuclear Information System (INIS)

    Efros, V.D.; Efros, V.D.; Leidemann, W.; Orlandini, G.; Orlandini, G.

    1997-01-01

    A four-nucleon calculation of the total 4 He photodisintegration cross section is performed. The full final-state interaction is taken into account for the first time. This is achieved via the method of the Lorentz integral transform. Semirealistic NN interactions are employed. Different from the known partial two-body 4 He( γ,n) 3 He and 4 He( γ,p) 3 H cross sections our total cross section exhibits a pronounced giant resonance. Thus, in contrast to older (γ,np) data, we predict quite a strong contribution of the (γ,np) channel at the giant resonance peak energy. copyright 1997 The American Physical Society

  18. Structure of the giant dipole resonance in 208Pb

    International Nuclear Information System (INIS)

    El Naggar, N.M.

    1977-01-01

    A new scheme is devised to study the giant resonance in the heavy magic nucleus 208 Pb. The effect of the 4 + and 5 - collective excitations of the nucleus core is demonstrated. The calculated cross section is compared with the experimental data. (author)

  19. Giant dipole resonances in hot nuclear matter in the model of self-relaxing mean field

    International Nuclear Information System (INIS)

    Okolowicz, J.; Ploszajczak, M.; Drozdz, S.; Caurier, E.

    1989-01-01

    The extended time-dependent Hartree-Fock approach is applied for the description of the isovector giant dipole resonance in 40 Ca at finite temperatures. The thermalization process is described using the relaxation-time ansatz for the collision integral. Strong inhibition of the giant-dipole-resonance γ-decay is found due to the fast vaporization of the nuclear surface for thermal excitation energies above E * /A ≅ 4.5 MeV. This pre-equilibrium emission of particles in the vapor phase is associated with the radial expansion of nucleus and with the vanishing particle binding energies mainly for protons. (orig.)

  20. Isovector giant dipole resonance in hot rotating light nuclei in the calcium region

    International Nuclear Information System (INIS)

    Shanmugam, G.; Thiagasundaram, M.

    1989-01-01

    The isovector giant dipole resonances in hot rotating light nuclei in the calcium region are studied using a rotating anisotropic harmonic oscillator potential and a separable dipole-dipole residual interaction. The influence of temperature on the isovector giant dipole resonance is assumed to occur through the change of deformation of the average field only. Calculations are performed for the three nuclei /sup 40,42/Ca and /sup 46/Ti which have spherical, oblate, and prolate ground states, respectively, to see how their shape transitions at higher excited states affect the isovector giant resonance frequencies built on them. It is seen that, while the width fluctuations present at T = 0 vanish at T = 0.5 MeV in /sup 40,42/Ca, they persist up to T = 1.5 MeV in the case of /sup 46/Ti. This behavior brings out the role of temperature on shell effects which in turn affects the isovector giant dipole resonance widths

  1. Thermal and rotational effect on giant dipole resonances in rotating nuclei at high temperature

    International Nuclear Information System (INIS)

    Sugawara-Tanabe, Kazuko; Tanabe, Kosai.

    1986-01-01

    Microscopic calculations are carried out for the giant dipole resonances excited on the thermal high spin states in 162 Er and 166 Er based on the thermal linear response theory with realistic forces and large single-particle space. The dynamical strength function is compared with the experimental γ-ray absorption cross section. The general trend that the resonance energy decreases and the resonance width increases with increasing angular momentum and temperature is well reproduced by the calculations. (author)

  2. Can we learn about the spin-flip giant dipole resonances with pions

    International Nuclear Information System (INIS)

    Baer, H.W.

    1982-01-01

    Data and calculations for the 40 Ca(π+-,π 0 ) reactions at 164 MeV are shown which indicate that pion scattering possesses a unique signature for separately identifying the 1 - and 2 - spin-isospin components of the giant dipole resonance

  3. The temperature dependence of the width of the giant-dipole resonance

    International Nuclear Information System (INIS)

    Ormand, W.E.; Bortignon, P.F.; Broglia, R.A.

    1996-01-01

    The giant-dipole resonance (GDR) in 120 Sn and 208 Pb is studied as a function of excitation energy, angular momentum, and intrinsic width within the context of the adiabatic model. Theoretical evaluations of the full-width-at-half-maximum (FWHM) for the GDR strength function are compared with recent experimental data and are found to be in good agreement. (orig.)

  4. Data systematics and semidirect decay probability of the giant dipole resonance

    International Nuclear Information System (INIS)

    Ishkhanov, B.S.; Kapitonov, I.M.; Tutyn', I.A.

    1998-01-01

    Information on probability of semidirect decay of giant dipole resonance of nuclei of sd- and fp-shells (A = 16-58) is elaborated on the base of the recent (γ, χγ ' ) experimental results. The shell effect in A-dependence of this probability is discovered

  5. Neutron-skin thickness from the study of the anti-analog giant dipole resonance

    NARCIS (Netherlands)

    Krasznahorkay, A.; Stuhl, L.; Csatlós, M.; Algora, A.; Gulyás, J.; Timár, J.; Paar, N.; Vretenar, D.; Boretzky, K.; Heil, M.; Litvinov, Yu A.; Rossi, D.; Scheidenberger, C.; Simon, H.; Weick, H.; Bracco, A.; Brambilla, S.; Blasi, N.; Camera, F.; Giaz, A.; Million, B.; Pellegri, L.; Riboldi, S.; Wieland, O.; Altstadt, S.; Fonseca, M.; Glorius, J.; Göbel, K.; Heftrich, T.; Koloczek, A.; Kräckmann, S.; Langer, C.; Plag, R.; Pohl, M.; Rastrepina, G.; Reifarth, R.; Schmidt, S.; Sonnabend, K.; Weigand, M.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Rigollet, C.; Bagchi, S.; Najafi, M. A.; Aumann, T.; Atar, L.; Heine, M.; Holl, M.; Movsesyan, A.; Schrock, P.; Volkov, V.; Wamers, F.; Fiori, E.; Löher, B.; Marganiec, J.; Savran, D.; Johansson, H. T.; Fernández, P. Diaz; Garg, U.; Balabanski, D. L.

    2012-01-01

    The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has been measured to the isobaric analog state excited in the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent random-phase

  6. A collective model description of the low lying and giant dipole resonant properties of 40424446Ca

    International Nuclear Information System (INIS)

    Weise, J.I.

    1982-01-01

    The low-lying and giant dipole resonant properties of the even-even calcium isotopes are calculated within the framework of the Gneuss-Greiner model and compared with the experimental data. In the low energy region, comparison is also made with the predictions of a coexistence model

  7. The giant-dipole-resonance effect in coulomb excitation of 10B

    International Nuclear Information System (INIS)

    Vermeer, W.J.; Zabel, T.H.; Esat, M.T.; Kuehner, J.A.; Spear, R.H.; Baxter, A.M.

    1982-04-01

    Coulomb excitation of the 0.718-MeV, Jsup(π) = 1 + , first excited state of 10 B has been studied using projectile excitation by 208 Pb and observing the backward scattered particles. The results give a clear indication of the virtual excitation of the giant dipole resonance as a second-order effect. The observed magnitude is consistent with the usual hydrodynamic model estimate and with a recent shell-model calculation

  8. Search for magnetic dipole strength and giant spin-flip resonances in heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Horen, D. J. [Oak Ridge National Lab., TN (USA); Ikegami, H.; Muraoka, M. [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

    1980-01-01

    A description is given of the use of high resolution (n, n) scattering and the (p, n) reaction as tools to investigate highly excited states with emphasis on information pertaining to magnetic dipole strength and giant spin-flip resonances in heavy nuclei. It is shown how the ability to uniquely determine the spins and parities of resonances observed in neutron scattering has been instrumental to an understanding of the distribution of M1 strength in sup(207,208)Pb. Some recent results of (p, n) studies with intermediate energy protons are discussed. Energy systematics of the giant Gamow-Teller (GT) resonance as well as a new ..delta..l = 1, ..delta..S = 1 resonance with J sup(..pi..) = (1,2)/sup -/ are presented. It is shown how the (p, n) reaction might be useful to locate M1 strength in heavy nuclei.

  9. Breaking of axial symmetry in excited heavy nuclei as identified in giant dipole resonance data

    Energy Technology Data Exchange (ETDEWEB)

    Grosse, E.; Massarczyk, R. [Technische Universitaet Dresden, Institute of Nuclear and Particle Physics, Dresden (Germany); Junghans, A.R. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Dresden (Germany)

    2017-11-15

    A recent theoretical prediction of a breaking of axial symmetry in quasi all heavy nuclei is confronted to a new critical analysis of photon strength functions of nuclei in the valley of stability. For the photon strength in the isovector giant dipole resonance (IVGDR) regime a parameterization of GDR shapes by the sum of three Lorentzians (TLO) is extrapolated to energies below and above the IVGDR. The impact of non-GDR modes adding to the low energy slope of photon strength is discussed including recent data on photon scattering and other radiative processes. These are shown to be concentrated in energy regions where various model calculations predict intermediate collective strength; thus they are obviously separate from the IVGDR tail. The triple Lorentzian (TLO) ansatz for giant dipole resonances is normalized in accordance to the dipole sum rule. The nuclear droplet model with surface dissipation accounts well for positions and widths without local, nuclide specific, parameters. Very few and only global parameters are needed when a breaking of axial symmetry already in the valley of stability is admitted and hence a reliable prediction for electric dipole strength functions also outside of it is expected. (orig.)

  10. Photoexcitation by gamma-ray scattering near threshold and giant dipole resonance

    International Nuclear Information System (INIS)

    Lakosi, L.; Safar, J.; Veres, A.; Sekine, T.; Kaji, H.; Yoshihara, K.

    1993-01-01

    Photoexcitation of 4.5 h half-life 115m In and 56 min half-life 103m Rh isomers by inelastic gamma-ray scattering near threshold and in the giant dipole resonance region has been reviewed. In disagreement with earlier experimental results available in the literature, but in good agreement with our experiments published recently, present calculations indicate that above the photoneutron emission threshold the isomer excitation drops abruptly and remains orders of magnitude smaller than at the threshold, even around resonance maximum. (author)

  11. Time-dependent shape fluctuations and the giant dipole resonance in hot nuclei: Realistic calculations

    International Nuclear Information System (INIS)

    Alhassid, Y.; Bush, B.; Yale Univ., New Haven, CT

    1990-01-01

    The effects of time-dependent shape fluctuations on the giant dipole resonance (GDR) in hot rotating nuclei are investigated. Using the framework of the Landau theory of shape transitions we develop a realistic macroscopic stochastic model to describe the quadrupole time-dependent shape fluctuations and their coupling to the dipole degrees of freedom. In the adiabatic limit the theory reduces to a previous adiabatic theory of static fluctuations in which the GDR cross section is calculated by averaging over the equilibrium distribution with the unitary invariant metric. Nonadiabatic effects are investigated in this model and found to cause structural changes in the resonance cross section and motional narrowing. Comparisons with experimental data are made and deviations from the adiabatic calculations can be explained. In these cases it is possible to determine from the data the damping of the quadrupole motion at finite temperature. (orig.)

  12. Damping of isovector giant dipole resonances in hot even-even spherical nuclei

    International Nuclear Information System (INIS)

    Dang, N.D.

    1989-01-01

    An approach based on the finite temperature quasiparticle phonon nuclear model (FT-QPNM) with the couplings to (2p2h) states at finite temperature taken into account is suggested for calculations of the damping of giant multipole resonances in hot even-even spherical nuclei. The strength functions for the isovector giant dipole resonance (IV-GDR) are calculated in 58 Ni and 90 Zr for a range of temperatures up to 3 MeV. The results show that the contribution of the interactions with (2p2h) configurations to the IV-GDR spreading width changes weakly with varying temperature. The IV-GDR centroid energy decreases slightly with increasing temperature. The nonvanishing superfluid pairing gap due to thermal fluctuations is included. (orig.)

  13. Atlas of giant dipole resonances. Parameters and graphs of photonuclear reaction cross sections

    International Nuclear Information System (INIS)

    Varlamov, A.V.; Varlamov, V.V.; Rudenko, D.S.; Stepanov, M.E.

    1999-01-01

    Parameters of giant dipole resonances (GDR) observed in photonuclear reaction cross sections using various beams of incident photons are presented. Data, given for 200 stable isotopes from 2 H to 243 Am including their natural compositions, were collected from papers published over the years 1951-1996. GDR parameters, such as energy positions, amplitudes and widths, are included into the table and organized by element, isotope and reaction. Graphs of the majority of the photonuclear reaction cross sections, included in the international nuclear data library EXFOR by the end of 1998, are presented. The graphs are provided for 182 stable isotopes and natural compositions. (author)

  14. A study of the giant dipole resonance in doubly even tellurium and cerium isotopes

    International Nuclear Information System (INIS)

    Lepretre, A.; Beil, H.; Bergere, R.; Carlos, P.; Fagot, J.; Miniac, A. de; Veyssiere, A.

    1976-01-01

    The partial photoneutron cross sections [sigma(γ,n)+sigma(γ,pn)] and sigma(γ,2n) of 124 Te, 126 Te, 128 Te, 130 Te and 140 Ce, 142 Ce were measured in the giant dipole resonance region by means of the monochromatic photon beam installation at SACLAY. Absolute total photoneutron cross sections, Lorentz line parameters and integrated cross sections are evaluated. The experimental behaviour of the GDR for the above nuclei and in particular its spreading, is then tentatively interpreted in terms of the improved dynamic collective model using the concept of potential energy surfaces. (Auth.)

  15. Studies of photonuclear reactions and photon activation analysis in the giant dipole resonance region using microtrons

    International Nuclear Information System (INIS)

    Tran Duc Thiep; Nguyen Van Do; Nguyen Khac Thi; Truong Thi An; Nguyen Ngoc Son

    2004-01-01

    Microtrons are accelerators of electrons and are simultaneous source of Bremsstrahlung photon flux and fission neutrons. In 1982, a microtron of seventeen trajectories Microtron MT - 17 was put into operation at the National Institute of Physics of Vietnam. Though very modest, microtrons are very useful for developing countries such as Vietnam in both fundamental and applied physics research. During the recent years by using the above mentioned MT - 17 and microtrons from other institutes we have carried out different investigation. In this report we present some results obtained in the studies of photonuclear reactions and photon activation analysis in the giant dipole resonance region. (author)

  16. Survey of the (3He,t) reaction: Excitation of the isobaric analog of the giant dipole resonance

    International Nuclear Information System (INIS)

    Tabor, S.L.; Chang, C.C.; Collins, M.T.; Wagner, G.J.; Wu, J.R.; Halderson, D.W.; Petrovich, F.

    1982-01-01

    The ( 3 He,t) reaction at 130 and 170 MeV has been investigated on targets of 12 C, 16 O, 27 Al, 28 Si, 40 Ca, 46 Ti, and 90 Zr. Data for the ( 3 He, 3 He') reaction were measured simultaneously for reference purposes. Structure is observed in the spectra from the ( 3 He, 3 He') and ( 3 He,t) reaction at the expected positions of the giant quadrupole resonance and the isobaric analog of the giant dipole resonance, respectively. An angular distribution was measured for the suspected giant dipole resonance structure in the 40 Ca( 3 He,t) 40 Sc reaction at 130 MeV. The data are reasonably described by a collective model calculation based on the Goldhaber-Teller model for the giant dipole resonance. Several other strong peaks at excitation energies below the giant dipole resonance are observed in the ( 3 He,t) spectra. Most notable of these are the ones at the expected positions for analogs of well known 1 + states and 1hω stretched states in the targets

  17. Deformation dependence of the isovector giant dipole resonance: The neodymium isotopic chain revisited

    Directory of Open Access Journals (Sweden)

    L.M. Donaldson

    2018-01-01

    Full Text Available Proton inelastic scattering experiments at energy Ep=200 MeV and a spectrometer scattering angle of 0° were performed on 144,146,148,150Nd and 152Sm exciting the IsoVector Giant Dipole Resonance (IVGDR. Comparison with results from photo-absorption experiments reveals a shift of resonance maxima towards higher energies for vibrational and transitional nuclei. The extracted photo-absorption cross sections in the most deformed nuclei, 150Nd and 152Sm, exhibit a pronounced asymmetry rather than a distinct double-hump structure expected as a signature of K-splitting. This behaviour may be related to the proximity of these nuclei to the critical point of the phase shape transition from vibrators to rotors with a soft quadrupole deformation potential. Self-consistent random-phase approximation (RPA calculations using the SLy6 Skyrme force provide a relevant description of the IVGDR shapes deduced from the present data.

  18. Deformation dependence of the isovector giant dipole resonance: The neodymium isotopic chain revisited

    Science.gov (United States)

    Donaldson, L. M.; Bertulani, C. A.; Carter, J.; Nesterenko, V. O.; von Neumann-Cosel, P.; Neveling, R.; Ponomarev, V. Yu.; Reinhard, P.-G.; Usman, I. T.; Adsley, P.; Brummer, J. W.; Buthelezi, E. Z.; Cooper, G. R. J.; Fearick, R. W.; Förtsch, S. V.; Fujita, H.; Fujita, Y.; Jingo, M.; Kleinig, W.; Kureba, C. O.; Kvasil, J.; Latif, M.; Li, K. C. W.; Mira, J. P.; Nemulodi, F.; Papka, P.; Pellegri, L.; Pietralla, N.; Richter, A.; Sideras-Haddad, E.; Smit, F. D.; Steyn, G. F.; Swartz, J. A.; Tamii, A.

    2018-01-01

    Proton inelastic scattering experiments at energy Ep = 200 MeV and a spectrometer scattering angle of 0° were performed on 144,146,148,150Nd and 152Sm exciting the IsoVector Giant Dipole Resonance (IVGDR). Comparison with results from photo-absorption experiments reveals a shift of resonance maxima towards higher energies for vibrational and transitional nuclei. The extracted photo-absorption cross sections in the most deformed nuclei, 150Nd and 152Sm, exhibit a pronounced asymmetry rather than a distinct double-hump structure expected as a signature of K-splitting. This behaviour may be related to the proximity of these nuclei to the critical point of the phase shape transition from vibrators to rotors with a soft quadrupole deformation potential. Self-consistent random-phase approximation (RPA) calculations using the SLy6 Skyrme force provide a relevant description of the IVGDR shapes deduced from the present data.

  19. Quantal and thermal dampings of the hot giant dipole resonance due to complex configuration mixing

    CERN Document Server

    Dang, N D; Arima, A

    1999-01-01

    An approach is presented to study the width of the giant dipole resonance (GDR) at non-zero temperature T, which includes all forward-going processes up to two-phonon ones. Calculations are performed in sup 1 sup 2 sup 0 Sn and sup 2 sup 0 sup 8 Pb. An overall agreement between theory and experiment is found. The total width of the GDR due to coupling of the GDR phonon to all ph, pp and hh configurations increases sharply as T increases up to T approx 3 MeV and saturates at T approx 4-6 MeV. The quantal width GAMMA sub Q due to coupling to ph configurations decreases with increasing T. It is almost independent of T if the contribution of two-phonon processes at T not =0 is omitted.

  20. Damping width of giant dipole resonances of cold and hot nuclei: A macroscopic model

    International Nuclear Information System (INIS)

    Mughabghab, S.F.; Sonzogni, A.A.

    2002-01-01

    A phenomenological macroscopic model of the giant dipole resonance (GDR) damping width of cold and hot nuclei with ground-state spherical and near-spherical shapes is developed. The model is based on a generalized Fermi liquid model which takes into account the nuclear surface dynamics. The temperature dependence of the GDR damping width is accounted for in terms of surface and volume components. Parameter-free expressions for the damping width and the effective deformation are obtained. The model is validated with GDR measurements of the following nuclides: 39,40 K, 42 Ca, 45 Sc, 59,63 Cu, 109-120 Sn, 147 Eu, 194 Hg, and 208 Pb, and is compared with the predictions of other models

  1. Study of the giant dipole resonance built on highly excited states in Sn and Dy nuclei

    International Nuclear Information System (INIS)

    Stolk, A.

    1988-01-01

    A study is presented of the giant dipole resonance built on highly excited states. The aim is to get more detailed information on the properties of the GDR and to use it as a tool for the investigation of nuclear structure at high excitation energy. The high energy γ-rays seen from the decay of excited state GDRs in heavy ion fusion reactions reflect the average properties of the states populated by the γ-emission. The measurements at different initial excitation energies of 114 Sn provide information on the nuclear level density near the particle separation energy at an average angular momentum of 10ℎ. The study of shape changes at very high spin in 152-156 Dy nuclei is presented. A theoretical model developed to describe fusion-evaporation reactions is presented. 149 refs.; 63 figs.; 13 tabs

  2. Origin of fine structure of the giant dipole resonance in s d -shell nuclei

    Science.gov (United States)

    Fearick, R. W.; Erler, B.; Matsubara, H.; von Neumann-Cosel, P.; Richter, A.; Roth, R.; Tamii, A.

    2018-04-01

    A set of high-resolution zero-degree inelastic proton scattering data on 24Mg, 28Si, 32S, and 40Ca provides new insight into the long-standing puzzle of the origin of fragmentation of the giant dipole resonance (GDR) in s d -shell nuclei. Understanding is achieved by comparison with random phase approximation calculations for deformed nuclei using for the first time a realistic nucleon-nucleon interaction derived from the Argonne V18 potential with the unitary correlation operator method and supplemented by a phenomenological three-nucleon contact interaction. A wavelet analysis allows one to extract significant scales both in the data and calculations characterizing the fine structure of the GDR. The fair agreement for scales in the range of a few hundred keV supports the surmise that the fine structure arises from ground-state deformation driven by α clustering.

  3. The 132Sn giant dipole resonance as a constraint on nuclear matter properties

    Science.gov (United States)

    Roach, Brandon; Bonasera, Giacomo; Shlomo, Shalom

    2015-10-01

    Nuclear giant resonances provide a sensitive method for constraining the properties of nuclear matter (NM) - many of which have large uncertainties - and thereby improve the nuclear energy-density functional. In this work, self-consistent Hartree-Fock random-phase approximation (HF-RPA) theory was employed to calculate the strength function and energy of the isovector giant dipole resonance (IVGDR) in the doubly-magic 132Sn nucleus. Several (17) commonly-used Skyrme-type interactions were employed. The correlations between the IVGDR centroid energy and each nuclear matter property were explored, as were correlations between the nuclear matter properties and the 132Sn neutron skin thickness rn -rp . Experimental data for the IVGDR centroid energy was used to constrain the symmetry energy density, the symmetry energy, and its first and second derivatives, respectively, of NM. Further investigation, particularly of nuclides far from stability, will be needed to extend the nuclear energy-density functional to the extremes of density and neutron abundance found in neutron stars and astrophysical nucleosynthesis environments.

  4. Main channels of the decay of the giant dipole resonance in the 20,22Ne nuclei and isospin splitting of the giant dipole resonance in the 22Ne nucleus

    International Nuclear Information System (INIS)

    Varlamov, V.V.; Stepanov, M.E.

    2002-01-01

    Data published in the literature on various photonuclear reactions for the 20,22 Ne isotopes and for their natural mixture are analyzed with the aim of exploring special features of the decay of giant-dipole-resonance states in these two isotopes. With the aid of data on the abundances of the isotopes and on the energy reaction thresholds, the cross sections for the reactions 20,22 Ne[(γ, n) + (γ, np)] and 20,22 Ne[(γ, p) + (γ, np)] are broken down into the contributions from the one-nucleon reactions (γ, n) and (γ, p) and the contributions from the reactions (γ, np). The cross sections evaporation model used here to treat the deexcitation of residual nucle(γ, p) 19,21 F in the energy range E γ = 16.0-28.0 MeV and the cross sections for the reactions 20,22 Ne(γ, np) 18,20 F in the energy range E γ = 23.3-28.0 MeV are estimated. The behavior of the cross-section ratio r = σ(γ, p)/σ(γ, n) for the 22 Ne nucleus as a function of energy is analyzed, and the isospin components of the giant dipole resonance in the 22 Ne nucleus are identified. The contributions of the isospin components of the giant dipole resonance in the 22 Ne nucleus to the cross sections for various photonuclear reactions are determined on the basis of an analysis of the diagram of the excitation and decay of pure isospin states in the 22 Ne nucleus and in nuclei neighboring it, which are members of the corresponding isospin multiplets. The isospin splitting of the giant dipole resonance and the ratio of the intensities of the isospin components are determined to be ΔE = 4.57 ± 0.69 MeV and R = 0.24 ± 0.04, respectively

  5. Elastic and Raman scattering of photons from the giant dipole resonance

    International Nuclear Information System (INIS)

    Bar-Noy, T.

    1978-12-01

    In the present work we investigated nuclear Raman and elastic scattering of photons from the Giant Dipole Resonance (GDR) of medium and heavy nuclei. The photons beams were obtained from thermal neutron capture on V, Fe, Ni, Cu and Cr discs, utilizing the IRR-2 reactor. Nine targets, 159 Tb, 165 Ho, 175 Lu, 181 Ta, 197 Au, 209 Bi, 232 Th, 237 Np, and 238 U, representing all spherical and deformed nuclei in the region of medium and heavy nuclei, were used. As preliminary works, we discovered and investigated the 11.4 MeV γ-line, measured the attenuation coefficients at 9 and 11.4 MeV, performed a numerical calculation of Delbrueck amplitudes and modified the Simple Rotator Model (SRM). The absolute scattering cross-sections were measured for each scatterer at 4-8 different energies, and angular distributions in the range 90 deg to 140 deg were carried out at 9 MeV and 11.4 MeV. The experimental results were compared with theoretical predictions of the modified SRM and the Dynamic Collective Model (DCM). The results proved that the modified SRM describes appropriately the scattering from the GDR, including elastic and Raman absolute cross-sections and their angular distributions. (author)

  6. QPM Analysis of 205Tl Nuclear Excitations below the Giant Dipole Resonance

    Science.gov (United States)

    Benouaret, N.; Beller, J.; Isaak, J.; Kelley, J. H.; Pai, H.; Pietralla, N.; Ponomarev, V. Yu.; Raut, R.; Romig, C.; Rusev, G.; Savran, D.; Scheck, M.; Schnorrenberger, L.; Sonnabend, K.; Tonchev, A. P.; Tornow, W.; Weller, H. R.; Zweidinger, M.

    2015-05-01

    We analysed our experimental recent findings of the dipole response of the odd-mass stable nucleus 205Tl within the quasi-particle phonon model. Using the phonon basis constructed for the neighbouring 204Hg and wave function configurations for 205Tl consisting of a mixture of quasiparticle ⊗ N-phonon configurations (N=0,1,2), only one group of fragmented dipole excited states has been reproduced at 5.5 MeV in comparison to the experimental distribution which shows a second group at about 5 MeV. The computed dipole transition strengths are mainly of E1 character which could be associated to the pygmy dipole resonance.

  7. QPM Analysis of 205Tl Nuclear Excitations below the Giant Dipole Resonance

    Directory of Open Access Journals (Sweden)

    Benouaret N.

    2015-01-01

    Full Text Available We analysed our experimental recent findings of the dipole response of the odd-mass stable nucleus 205Tl within the quasi-particle phonon model. Using the phonon basis constructed for the neighbouring 204Hg and wave function configurations for 205Tl consisting of a mixture of quasiparticle ⊗ N-phonon configurations (N=0,1,2, only one group of fragmented dipole excited states has been reproduced at 5.5 MeV in comparison to the experimental distribution which shows a second group at about 5 MeV. The computed dipole transition strengths are mainly of E1 character which could be associated to the pygmy dipole resonance.

  8. Giant nuclear resonances

    International Nuclear Information System (INIS)

    Snover, K.A.

    1989-01-01

    Giant nuclear resonances are elementary mods of oscillation of the whole nucleus, closely related to the normal modes of oscillation of coupled mechanical systems. They occur systematically in most if not all nuclei, with oscillation energies typically in the range 10-30 MeV. One of the best - known examples is the giant electric dipole (El) resonance, in which all the protons and all the neutrons oscillate with opposite phase, producing a large time - varying electric dipole moment which acts as an effective antenna for radiating gamma ray. This paper discusses this mode as well as quadrupole and monopole modes

  9. Dipole strength distribution below the giant dipole resonance in {sup 92}Mo, {sup 98}Mo and {sup 100}Mo

    Energy Technology Data Exchange (ETDEWEB)

    Rusev, G.Y.

    2006-07-01

    Investigations of the dipole-strength distributions in {sup 92}Mo, {sup 98}Mo and {sup 100}Mo were carried out by means of the method of nuclear resonance fluorescence. The low-lying excitations in the nuclides {sup 92}Mo, {sup 98}Mo and {sup 100}Mo have been studied in photon-scattering experiments at an electron energy of 6 MeV at the ELBE accelerator and at electron energies from 3.2 to 3.8 MeV at the Dynamitron accelerator. Five levels were observed in {sup 92}Mo. Five levels in {sup 98}Mo and 14 in {sup 100}Mo were identified for the first time in the energy range from 2 to 4 MeV. Dipole-strength distributions up to the neutron-separation energies in the nuclides {sup 92}Mo, {sup 98}Mo and {sup 100}Mo have been investigated at the ELBE accelerator. Because of the possible observation of transitions in the neighboring nuclei produced via ({gamma},n) reaction, additional measurements at electron energies of 8.4 and 7.8 MeV, below the neutron-separation energy, were performed on {sup 98}Mo and {sup 100}Mo, respectively. The number of transitions assigned to {sup 92}Mo, {sup 98}Mo and {sup 100}Mo is 340, 485 and 499, respectively, the main part of them being dipole transitions. Statistical properties of the observed transitions are obtained. The continuum contains the ground-state transitions as well as the branching transitions to the low-lying levels and the subsequent deexcitations of these levels. (orig.)

  10. Empty-electronic-state evolution for Sc and electron dynamics at the 3p-3d giant dipole resonance

    International Nuclear Information System (INIS)

    Hu, Y.; Wagener, T.J.; Gao, Y.; Weaver, J.H.

    1989-01-01

    Inverse photoemission has been used to study the developing electronic states of an early transition metal, Sc, during thin-film growth and to investigate the effects of these states on the 3p-3d giant dipole resonance. Energy- and coverage-dependent intensity variations of the empty Sc states show that the 3d maximum moves 1.1 eV toward the Fermi level as the thickness of the Sc film increases from 1 to 300 A as measured with an incident electron energy of 41.25 eV, an effect attributed to metallic band formation via hybridization of atomic 4s and 3d states. Incident-energy-dependent intensity variations for these empty Sc features show resonant photon emission for incident electron energies above the 3p threshold, with maxima at 43 and 44 eV for 300- and 5-A-thick films, respectively. Considerations of hybridization-induced energy shifts of the empty Sc 3d states demonstrate that the radiative energy changes very little with Sc coverages. These studies indicate coupling of decay channels involving the inverse photoemission continuum and the recombination of the atomic 3p-3d giant dipole transition, the energy of the latter being determined by atomic 3p-3d excitation processes

  11. Isotopic effect giant resonances

    International Nuclear Information System (INIS)

    Buenerd, M.; Lebrun, D.; Martin, P.; Perrin, G.; Saintignon, P. de; Chauvin, J.; Duhamel, G.

    1981-10-01

    The systematics of the excitation energy of the giant dipole, monopole, and quadrupole resonances are shown to exhibit an isotopic effect. For a given element, the excitation energy of the transition decreases faster with the increasing neutron number than the empirical laws fitting the overall data. This effect is discussed in terms of the available models

  12. Heavy ion coulomb excitation and gamma decay studies of the one and two phonon giant dipole resonances in 208Pb and 209Bi

    International Nuclear Information System (INIS)

    Mueller, P.E.; Beene, J.R.; Bertrand, F.E.; Halbert, M.L.; Olive, D.H.; Varner, R.L.; Sherrill, B.; Thoennessen, M.; Lautridou, P.; Lefevre, F.; Marques, M.; Matulewicz, T.; Mittig, W.; Ostendorf, R.; Roussel-Chomaz, P.; Schutz, Y.; Pol, J. van; Wilschut, H.W.; Diaz, J.; Ferrero, J.L.; Marin, A.

    1994-01-01

    Projectile - phonon coincidences were measured for the scattering of an 80 MeV/nucleon 64 Zn beam from 208 Pb and 209 Bi targets at the GANIL heavy ion accelerator facility. Projectile-like particles between 0.5 and 4.5 relative to the incident beam direction were detected in the SPEG energy loss spectrometer where their momentum, charge, and mass were determined. Photons were detected in the BaF 2 scintillation detector array TAPS. Light charged particles produced in the reaction were detected in the KVI Forward Wall. The analysis of the data acquired in this experiment is focused on three different phenomena: (1) the two phonon giant dipole resonance, (2) time dependence of the decay of the one phonon giant dipole resonance, and (3) giant resonance strength in projectile nuclei. (orig.)

  13. Giant Primeval Magnetic Dipoles

    Science.gov (United States)

    Thompson, Christopher

    2017-07-01

    Macroscopic magnetic dipoles are considered cosmic dark matter. Permanent magnetism in relativistic field structures can involve some form of superconductivity, one example being current-carrying string loops (“springs”) with vanishing net tension. We derive the cross-section for free classical dipoles to collide, finding it depends weakly on orientation when mutual precession is rapid. The collision rate of “spring” loops with tension { T }˜ {10}-8{c}4/G in galactic halos approaches the measured rate of fast radio bursts (FRBs) if the loops compose most of the dark matter. A large superconducting dipole (LSD) with mass ˜1020 g and size ˜1 mm will form a ˜100 km magnetosphere moving through interstellar plasma. Although hydromagnetic drag is generally weak, it is strong enough to capture some LSDs into long-lived rings orbiting supermassive black holes (SMBHs) that form by the direct collapse of massive gas clouds. Repeated collisions near young SMBHs could dominate the global collision rate, thereby broadening the dipole mass spectrum. Colliding LSDs produce tiny, hot electromagnetic explosions. The accompanying paper shows that these explosions couple effectively to propagating low-frequency electromagnetic modes, with output peaking at 0.01-1 THz. We describe several constraints on, and predictions of, LSDs as cosmic dark matter. The shock formed by an infalling LSD triggers self-sustained thermonuclear burning in a C/O (ONeMg) white dwarf (WD) of mass ≳1 M ⊙ (1.3 M ⊙). The spark is generally located off the center of the WD. The rate of LSD-induced explosions matches the observed rate of Type Ia supernovae.

  14. Effect of large neutron excess in the region of the Giant Dipole and Quadrupole Resonance

    CERN Document Server

    Lanza, E G

    1999-01-01

    We study the dipole and quadrupole modes of neutron rich nuclei within the selfconsistent HF + RPA. The presence of neutron skin enhances the mixing of isoscalar and isovector modes. Then it is possible to excite modes of isovector character by an isoscalar probe. In particular we analize the excitation of dipole modes by alpha scattering. The excitation of compressional isoscalar mode is also studied.

  15. On Landau Vlasov simulations of giant resonances

    International Nuclear Information System (INIS)

    Pi, M.; Schuck, P.; Suraud, E.; Gregoire, C.; Remaud, B.; Sebille, F.

    1987-05-01

    We present VUU calculations of giant resonances obtained in energetic heavy ion collisions. Also is considered the case of the giant dipole in 40 Ca and the possibility of studying the effects of rotation on such collective modes

  16. Self-consistent treatment of nuclear collective motion with an application to the giant-dipole resonance

    International Nuclear Information System (INIS)

    Liran, S.; Technion-Israel Inst. of Tech., Haifa. Dept. of Physics)

    1977-01-01

    This paper extends the recent theory of Liran, Scheefer, Scheid and Greiner on non-adiabatic cranking and nuclear collective motion. In the present work we show the self-consistency conditions for the collective motion, which are indicated by appropriate time-dependent Lagrange multipliers, can be treated explicitly. The energy conservation and the self-consistency condition in the case of one collective degree of freedom are expressed in differential form. This leads to a set of coupled differential equations in time for the many-body wave function, for the collective variable and for the Lagrange multiplier. An iteration procedure similar to that of the previous work is also presented. As an illustrative example, we investigate Brink's single-particle description of the giant-dipole resonance. In this case, the important role played by non-adiabaticity and self-consistency in determining the collective motion is demonstrated and discussed. We also consider the fact that in this example of a fast collective motion, the adiabatic cranking model of Inglis gives the correct mass parameter. (orig.) [de

  17. Improvement of photoneutron spectrum measurement produced by bombardment of 2 GeV electrons above giant dipole resonance region

    International Nuclear Information System (INIS)

    Lee, H. S.; Park, J. S.; Choi, H. D.; Sato, Tatsuhiko; Shin, Kasuo; Ban, Syuichi

    2000-01-01

    Above the Giant Dipole Resonance (GDR) region, high energy photoneutron spectra produced by irradiation of 2.04 GeV electrons into Pb target were measured by Time-of-Flight (TOF) technique. The differential photoneutron yields were obtained at a fixed angle of 90 degrees to the electron beam direction. The TOF system consists of Pilot-U plastic scintillation detector, which has fast response time, and the high speed multiscaler or CAMAC TDC. In the improvement of experimental setup to extend the flight distance to 10.4 m lead to make the measurable energy to 500 MeV from 300 MeV. And using the TDC based electronics lead to use a veto counter. The results were compared with the calculated one by using EGS4 and Modified PICA95. The characteristics of this TOF system was introduced in this paper and the results for several measuring conditions, which are flight distance, TOF electronics, and type of neutron detector, were discussed to improve the accuracy of this measurement

  18. Isomeric ratios in photonuclear reactions of molybdenum isotopes induced by bremsstrahlung in the giant dipole resonance region

    International Nuclear Information System (INIS)

    Tran Duc Thiep; Truong Thi An; Phan Viet Cuong; Nguyen The Vinh; Bui Minh Hue; Belov, A.G.; Maslov, O.D.; Mishinsky, G.V.; Zhemenik, V.I.

    2017-01-01

    We have determined the isomeric ratios of isomeric pairs "9"7"m","gNb, "9"5"m","gNb and "9"1"m","gMo produced in "9"8Mo(γ, p)"9"7"m","gNb, "9"6Mo(γ, p)"9"5"m","gNb and "9"2Mo(γ, n)"9"1"m","gMo photonuclear reactions in the giant dipole resonance (GDR) region by the activation method. The results were analyzed, discussed and compared with the similar data from literature to examine the role of excitation energy, neutron configuration, channel effect, and direct and pre-equilibrium processes in (γ, p) photonuclear reactions. In this work the isomeric ratios for "9"7"m","gNb from 14 to 19 MeV, for "1"9"5"m","gNb from 14 to 24 MeV except 20 and 23.5 MeV and for "9"1"m","gMo at 14 and 15 MeV were first measured.

  19. Properties of Hot and Fast Rotating Atomic Nuclei Studied by Means of Giant Dipole Resonance in Exclusive Experiments

    International Nuclear Information System (INIS)

    Maj, A.

    2000-01-01

    This work entitled ''Properties of hot and fast rotating atomic nuclei studied by means of Giant Dipole Resonance in exclusive experiments'', is the habilitation thesis of dr. Adam Maj. It consists of the review (in Polish) of performed research and of attached reprints from 16 original publications (in English) which A. Maj is the main or one of the main authors. All the studies were performed in collaboration with the groups from Milano and Copenhagen, using the HECTOR array equipment (described in chapter V). The Giant Dipole Resonance couples to the quadrupole degrees of freedom of the nucleus, and therefore constitutes a unique probe to test the shapes of atomic nuclei. In addition, the γ decay of the GDR from highly excited nuclei is a very fast process, it can compete with other modes of nuclear decay, and therefore can provide the information on the initial stages of excited nuclei. The presented investigations were concentrated on the following aspects: the shapes and thermal shape fluctuations, the origin of the behaviour of the GDR width, the properties of some exotic nuclei (Jacobi shapes, superdeformation, superheavy nuclei) and on ''entrance channel'' effects. The GDR γ decay was measured for nuclei with very different masses: from light nuclei with A≅45, through A≅110, 145,170,190, up to superheavy nuclei with A≅270. The shapes of hot nuclei are not fixed but fluctuate. The extent of these fluctuations and their influence on the measured quantities (GDR strength function, angular distribution and effective shape) is discussed in chapter VI.1. The observed width of the GDR is found to arise from the interplay of two effects: the thermal shape fluctuations, which are controlled by the nuclear temperature, and the deformation effects, controlled by the angular momentum. The ''collisional damping'' effect, which should influence the intrinsic GDR width, was found to be negligible (chapter VI.2). The GDR γ decay from hot superheavy nucleus 272 Hs

  20. Comment on 'Angular momentum gated giant dipole resonance measurements in the reaction 28Si+58Ni at E(28Si)=100 and 125 MeV'

    International Nuclear Information System (INIS)

    Heckman, P.; Thoennessen, M.

    2003-01-01

    In a recent paper, the giant dipole resonance width was studied as a function of angular momentum in the nucleus 86 Mo. The width of the resonance was found to be constant over a spin range of (0-40)(ℎ/2π). It was concluded that the angular momentum dependence for 86 Mo differs from that of Sn isotopes. We compared both datasets with a phenomenological formula based on the thermal fluctuation theory. The 86 Mo data are inconsistent with the formula in contrast to the previously analyzed Sn data, which seems to indicate that the angular momentum dependence of the phenomenological model is not universally applicable

  1. Calculations of the giant-dipole-resonance photoneutrons using a coupled EGS4-morse code

    International Nuclear Information System (INIS)

    Liu, J.C.; Nelson, W.R.; Kase, K.R.; Mao, X.S.

    1995-10-01

    The production and transport of the photoneutrons from the giant-dipoleresonance reaction have been implemented in a coupled EGS4-MORSE code. The total neutron yield (including both the direct neutron and evaporation neutron components) is calculated by folding the photoneutron yield cross sections with the photon track length distribution in the target. Empirical algorithms based on the measurements have been developed to estimate the fraction and energy of the direct neutron component for each photon. The statistical theory in the EVAP4 code, incorporated as a MORSE subroutine, is used to determine the energies of the evaporation neutrons. These represent major improvements over other calculations that assumed no direct neutrons, a constant fraction of direct neutrons, monoenergetic direct neutron, or a constant nuclear temperature for the evaporation neutrons. It was also assumed that the slow neutrons ( 2 θ, which have a peak emission at 900. Comparisons between the calculated and the measured photoneutron results (spectra of the direct, evaporation and total neutrons; nuclear temperatures; direct neutron fractions) for materials of lead, tungsten, tantalum and copper have been made. The results show that the empirical algorithms, albeit simple, can produce reasonable results over the interested photon energy range

  2. Width and strength of the hot giant dipole resonance. The role of the life time of the compound nucleus and the transition from order to chaos

    International Nuclear Information System (INIS)

    Chomaz, P.

    1996-01-01

    A bump in the γ decay spectrum is observed at high energies which is due to the excitation of the Giant Dipole Resonance (GDR) in the compound nucleus. The fact is discussed that the total width of the γ-ray spectrum of the GDR transitions must contain twice the width of the compound nucleus levels. This implies that one must except a rapid increase of the width of the GDR. This increase contributes to the observed saturation of the photon multiplicity. A new suppression factor due to the lost of collectivity induced by the fast particle emission is proposed. (K.A.)

  3. Isoscalar giant resonances

    Energy Technology Data Exchange (ETDEWEB)

    Youngblood, D. H. [Texas A and M Univ., College Station (USA). Cyclotron Inst.; Ikegami, H.; Muraoka, M. [eds.

    1980-01-01

    The current status of the knowledges of giant quadrupole resonance (GQR), low energy octupole resonance (LEOR), and giant monopole resonance (GMR), is described. In the lowest order of multipole resonance, both isoscalar and isovector modes can occur. The characteristics of the GQR in light nuclei are apparent in the experimental result for Mg-24. All of the isoscalar E2 strength are known in Mg-24. The Goldhaber-Teller model is preferred over the Steinwedel-Jensen model for the giant dipole resonance (GDR) transition density. A few interesting and puzzling features have been seen in Pb-208. There is some conflict between inelastic alpha and electron scatterings. About LEOR, the RPA calculation of Liu and Brown was compared to the data for 3/sup -/ strength in Ca-40, Zr-90 and Pb-208. The calculation was employed the residual interaction of the Skyrme type. The agreement in Zr-90 was excellent. The effect of quadrupole deformation on the LEOR in Sm isotopes was large. The inelastic alpha scattering data on Al-27, Ca-40, Ti-48, Ni-58, Zn-64 and 66, Zr-90, Sn-116, 118, 120 and 124, Sm-144, 148 and 154, and Pb-208 were utilized in order to identify the GMR, and the GMR parameters were obtained. The GMR exhausting a large fraction of the sum rule was apparent in the nuclei with mass larger than 90. The splitting of the GDR and the broadening of the GQR in permanently deformed nuclei were established. The splitting of GMR was seen in Sm-154. The studies with heavy ions are also described.

  4. The isomeric ratios in photonuclear reactions of natural barium induced by bremsstrahlungs with endpoint energies in the giant dipole resonance region

    International Nuclear Information System (INIS)

    Tran Duc Thiep; Truong Thi An; Phan Viet Cuong; Nguyen The Vinh

    2012-01-01

    We have determined the isomeric ratios in 130 Ba(γ, n) 129m,g Ba, 132 Ba(γ, n) 131m,g Ba and 134 Ba(γ, n) 133m,g Ba photonuclear reactions of natural barium induced by bremsstrahlungs with end-point energies in the giant dipole resonance region. The investigated samples were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The gamma spectra of the samples irradiated were measured with spectroscopic system consisting of 8192 channel analyzer and high-energy resolution (180 keV at gamma ray 1332 keV of 60 Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results were discussed and compared with those of other authors. (author)

  5. Multipole giant resonances in highly excited nuclei

    International Nuclear Information System (INIS)

    Xia Keding; Cai Yanhuang

    1989-01-01

    The isoscalar giant surface resonance and giant dipole resonance in highly excited nuclei are discussed. Excitation energies of the giant modes in 208 Pb are calculated in a simplified model, using the concept of energy wieghted sum rule (EWSR), and the extended Thomas-Fermi approximation at the finite temperature is employed to describe the finite temperature is employed to describe the finite temperature equilibrium state. It is shown that EWSR and the energy of the resonance depend only weakly on temperature in the system. This weak dependence is analysed

  6. 'Bi-modal' isoscalar giant dipole strength in 58Ni

    International Nuclear Information System (INIS)

    Nayak, B.K.; Garg, U.; Hedden, M.; Koss, M.; Li, T.; Liu, Y.; Madhusudhana Rao, P.V.; Zhu, S.; Itoh, M.; Sakaguchi, H.; Takeda, H.; Uchida, M.; Yasuda, Y.; Yosoi, M.; Fujimura, H.; Fujiwara, M.; Hara, K.; Kawabata, T.; Akimune, H.; Harakeh, M.N.

    2006-01-01

    The strength distribution of the isoscalar giant dipole resonance (ISGDR) in 58 Ni has been obtained over the energy range 10.5-49.5 MeV via extreme forward angle scattering (including 0 deg.) of 386 MeV α particles. We observe a 'bi-modal' E1 strength distribution for the first time in an A<90 nucleus. The observed ISGDR strength distribution is in reasonable agreement with the predictions of a recent RPA calculation

  7. Dipole Resonances of 76Ge

    Science.gov (United States)

    Ilieva, R. S.; Cooper, N.; Werner, V.; Rusev, G.; Pietralla, N.; Kelly, J. H.; Tornow, W.; Yates, S. W.; Crider, B. P.; Peters, E.

    2013-10-01

    Dipole resonances in 76Ge have been studied using the method of Nuclear Resonance Fluorescence (NRF). The experiment was performed using the Free Electron Laser facility at HI γS/TUNL, which produced linearly polarised quasi-monoenergetic photons in the 4-9 MeV energy range. Photon strength, in particular dipole strength, is an important ingredient in nuclear reaction calculations, and recent interest in its study has been stimulated by observations of a pygmy dipole resonance near the neutron separation energy Sn of certain nuclei. Furthermore, 76Ge is a candidate for 0 ν 2 β -decay. The results are complimentary to a relevant experiment done at TU Darmstadt using Bremsstrahlung beams. Single-resonance parities and a preliminary estimate of the total photo-excitation cross section will be presented. This work was supported by the U.S. DOE under grant no. DE-FG02-91ER40609.

  8. Nuclear isovector giant resonances excited by pion single charge exchange

    International Nuclear Information System (INIS)

    King, B.H.

    1993-07-01

    This thesis is an experimental study of isovector giant resonances in light nuclei excited by pion single charge exchange reactions. Giant dipole resonances in light nuclei are known to be highly structured. For the mass 9 and 13 giant dipole resonances, isospin considerations were found to be very important to understanding this structure. by comparing the excitation functions from cross section measurements of the (π + , π 0 ) and (π, π 0 ) inclusive reactions, the authors determined the dominant isospin structure of the analog IVGR's. The comparison was made after decomposing the cross section into resonant and non-resonant components. This decomposition is made in the framework of strong absorption and quasi-free scattering. Measurements in the region of the isovector giant dipole resonances (IVGDR) were made to cover the inclusive angular distributions out to the second minimum. Study of the giant resonance decay process provides further understanding of the resonances. This study was carried out by observing the (π + , π 0 p) coincident reactions involving the resonances of 9 B and 13 N excited from 9 Be and 13 C nuclei. These measurements determined the spectra of the decay protons. This method also permitted a decomposition of the giant resonances into their isospin components. The multipolarities of the resonances were revealed by the decay proton angular correlations which, for dipoles, are of the form 1 + A 2 P 2 (cos θ)

  9. Excitation of giant resonances through inelastic scattering

    International Nuclear Information System (INIS)

    Kailas, S.

    1981-01-01

    In the last few years, exciting developments have taken place in the study of giant resonances (GR). In addition to the already well known gjant dipole resonance (GDR), the presence of at least two more new GRs viz. giant quadrupole resonance (GQR) and giant monopole resonance (GMR) has been experimentally established. The systematics covering these GRs is found to be consistent with the theoretical expectation. Though the existence of higher multipoles has been predjcted by theory, so far only some of these have been found to be excited experimentally. Various probe particles - electrons, protons (polarized and unpolarized), light and heavy ions and pions - at different bombarding energies have been used to excite the GR region, primarily through the inelastic scattering process. Detailed experiments, looking at the decay modes of GR region, have also been performed. These studies have contributed significantly to a better understanding of the phenomenon of nuclear collective excitation. In this report, the current status of 'GR' research is reviewed. (author)

  10. New properties of giant resonances in highly excited nuclei

    International Nuclear Information System (INIS)

    Morsch, H.P.

    1991-01-01

    Studies on the giant dipole resonance in very hot nuclei investigated in heavy ion-induced particle-γ coincidence experiments are reviewed. A signature is found in the γ-decay of excited nuceli which shows direct decay of the giant dipole resonance. This provides a new dimension in giant resonance studies and the possibility to study the dependence of giant resonance energy, width and sum rule strength on excitation energy and rotation of the system. Further, the fact that the giant resonance splits in deformed nuclei provides a unique way to get information on the shape of hot nuclei. First results are obtained on the following questions: (i)What is the nuclear shape at high temperature (T≥2 MeV)? (ii)Is there a phase transition in the nuclear shape at T∼1.7 MeV? (iii)Does motional narrowing exist in hot nuclei? (author). 19 refs., 11 figs

  11. Splitting of the Pygmy Dipole Resonance

    International Nuclear Information System (INIS)

    Endres, J.; Zilges, A.; Butler, P.; Herzberg, R.-D.; Scheck, M.; Harakeh, M. N.; Harissopulos, S.; Lagoyannis, A.; Kruecken, R.; Ring, P.; Litvinova, E.; Pietralla, N.; Ponomarev, V. Yu.; Sonnabend, K.; Popescu, L.; Savran, D.; Stoica, V. I.; Woertche, H. J.

    2011-01-01

    In recent years investigations have been made to study the electric Pygmy Dipole Resonance (PDR) systematically, mainly in semi-magic nuclei. For this purpose the well understood high resolution (γ,γ') photon scattering method is used. In complementary (α,α'γ) coincidence experiments at E α = 136 MeV a similar γ-energy resolution and a high selectivity to E1 transitions can be obtained at the Big-Bite Spectrometer (BBS) at KVI, Groningen. In comparison to the (γ,γ') method a structural splitting of the PDR is observed in the N = 82 nuclei 138 Ba and 140 Ce and in the Z = 50 nucleus 124 Sn. The low energy part is excited in (γ,γ') as well as in (α,α'γ) while the high energy part is observed in (γ,γ') only. The experimental results together with theoretical QPM and RQTBA calculations on 124 Sn which are able to reproduce the splitting of the PDR qualitatively are presented. The low-lying group of J π = 1 - states seem to represent the more isoscalar neutron-skin oscillation of the PDR while the energetically higher-lying states seemingly belong to the transitional region between the PDR and the isovector Giant Dipole Resonance (IVGDR).

  12. Electroexcitation of giant resonances in 181Ta

    International Nuclear Information System (INIS)

    Hicks, R.S.; Auer, I.P.; Bergstrom, J.C.; Caplan, H.S.

    1977-01-01

    The giant resonance region of 181 Ta has been investigated by means of inelastic electron scattering with primary electron energies of 79.1 to 118.3 MeV. A peak-fitting procedure was employed to separate the measured spectrum into nine different resonance components. Multipolarity and strength assignments were deduced using DWBA analysis with the Goldhaber-Teller and Steinwedel-Jensen models. In addition to the well-known giant dipole structure, other resonances were identified at 23.2+-0.3 MeV (E2), 9.5+-0.2 and 11.5+-0.2 MeV (E2 or E0), 19.5+-0.8 MeV (E3), 3.70+-0.14 MeV (E3 or E4), and 5.40+-0.15 MeV (E4 or E5). The model dependence of the analysis is discussed. (Auth.)

  13. Study of giant resonances in heavy nuclei

    International Nuclear Information System (INIS)

    Cataldi, M.I.C.

    1986-01-01

    The electrodisintegration cross section for 181 Ta, 208 Pb and 209 Bi was measured by counting the emitted neutrons, with incident electrons in the energy range 8-22 MeV. The data was analysed using the virtual photon method, in order to obtain a multipole decomposition and the intensities of Magnetic Dipole and Electric Quadrupole, isoscalar and isovector, in the Giant Resonance. The results obtained for the isovector Giant Quadrupole Resonance are compared with the measured photodisintegration cross section, using data from Saclay and Livermore. This comparision indicates that the photodisintegration data can be well explained assuming an isovector E2 Resonance located between 120 and 130 A -1/3 MeV, with an intensity of one isovector E2 sum. (author) [pt

  14. Isotopic dependence of giant multipole resonances

    International Nuclear Information System (INIS)

    Bar Touv, J.; Moalem, A.; Shlomo, S.

    1980-01-01

    A procedure is presented which allows the application of linear response theory and the random phase approximation to an open shell. The procedure is applied to Ca isotopes. The general features of giant multipole resonances are found to vary smoothly with the mass. The resonances exhibit more structure in the open lfsub(7/2) shell nuclei. While the energy-weighted dipole sum is practically constant in all isotopes, the isoscalar quadrupole and octupole energy weighted sums increase continuously by approx. 30% from 40 Ca to 48 Ca. (orig.)

  15. Hadron excitation of giant resonances

    International Nuclear Information System (INIS)

    Morsch, H.-P.

    1985-01-01

    A review is given on giant resonance studies in heavy nuclei using scattering of different hadronic probes. Concerning isoscalar giant resonances compression modes are discussed with the possibility to obtain more detailed structure information. From detailed studies of α scattering the distribution of isoscalar strengths of multipolarity up to L=6 was obtained. Some recent aspects of heavy ion excitation of collective modes are mentioned. The possibility to study isovector giant resonances in hadron charge exchange reactions is discussed. Finally, a comparison is made between α and 200 MeV proton scattering from which isoscalar and spin-isospin continuum response are extracted. (orig.)

  16. Overtones of isoscalar giant resonances studied in direct particle decay measurements

    NARCIS (Netherlands)

    Hunyadi, M; van den Berg, AM; Csatlos, M; Csige, L; Davids, B; Garg, U; Gulyas, J; Harakeh, MN; de Huu, MA; Krasznahorkay, A; Sohler, D; Wortche, HJ

    The isoscalar giant dipole resonance (ISGDR), which is the lowest-energy overtone mode of the isoscalar giant resonances, has been studied in some medium-heavy and heavy nuclei in coincidence measurements. The observation of the direct nucleon decay channels significantly helped to enhance giant

  17. Relativistic Coulomb excitation of giant resonances in the hydrodynamic model

    International Nuclear Information System (INIS)

    Vasconcellos Gomes, Ana Cristina de.

    1990-05-01

    We investigate the Coulomb excitation of giant dipole resonances in relativistic heavy ion collisions using a macroscopic hydrodynamical model for the harmonic vibrations of the nuclear fluid. The motion is treated as a combination of the Goldhaber-Teller displacement mode and the Steinwedel-Jensen acoustic mode, and the restoring forces are calculated using the droplet model. This model is used as input to study the characteristics of multiple excitation of giant dipole resonances in nuclei. Possible signatures for the existence of such states are also discussed quantitatively. (author). 52 refs., 14 figs., 3 tabs

  18. Dependence of the giant dipole strength function on excitation energy

    International Nuclear Information System (INIS)

    Draper, J.E.; Newton, J.O.; Sobotka, L.G.; Lindenberger, H.; Wozniak, G.J.; Moretto, L.G.; Stephens, F.S.; Diamond, R.M.; McDonald, R.J.

    1982-01-01

    Spectra of γ rays associated with deep-inelastic products from the 1150-MeV 136 Xe+ 181 Ta reaction have been measured. The yield of 10--20-MeV γ rays initially increases rapidly with the excitation energy of the products and then more slowly for excitation energies in excess of 120 MeV. Statistical-model calculations with ground-state values of the giant dipole strength function fail to reproduce the shape of the measured γ-ray spectra. This suggests a dependence of the giant dipole strength function on excitation energy

  19. Statistical decay of giant resonances

    International Nuclear Information System (INIS)

    Dias, H.; Teruya, N.; Wolynec, E.

    1986-01-01

    Statistical calculations to predict the neutron spectrum resulting from the decay of Giant Resonances are discussed. The dependence of the resutls on the optical potential parametrization and on the level density of the residual nucleus is assessed. A Hauser-Feshbach calculation is performed for the decay of the monople giant resonance in 208 Pb using the experimental levels of 207 Pb from a recent compilation. The calculated statistical decay is in excelent agreement with recent experimental data, showing that the decay of this resonance is dominantly statistical, as predicted by continuum RPA calculations. (Author) [pt

  20. Statistical decay of giant resonances

    International Nuclear Information System (INIS)

    Dias, H.; Teruya, N.; Wolynec, E.

    1986-02-01

    Statistical calculations to predict the neutron spectrum resulting from the decay of Giant Resonances are discussed. The dependence of the results on the optical potential parametrization and on the level density of the residual nucleus is assessed. A Hauser-Feshbach calculation is performed for the decay of the monopole giant resonance in 208 Pb using the experimental levels of 207 Pb from a recent compilation. The calculated statistical decay is in excellent agreement with recent experimental data, showing that decay of this resonance is dominantly statistical, as predicted by continuum RPA calculations. (Author) [pt

  1. New results on multiple excitations of giant resonances

    International Nuclear Information System (INIS)

    Mordechai, S.; Texas Univ., Austin, TX; Moore, C.F.

    1993-01-01

    Exotic excitations like the double giant dipole were predicted for many years but not observed experimentally until recently. Several experiments have been carried out at Los Alamos National laboratory to search for these new collective modes of the nucleus. The results discover two previously unobserved types of double giant resonances. This work presents the recent pion double charge exchange data and the analysis that support the existence of two such exotic vibrational nuclear modes

  2. Giant dipole modes in heavy-ion reactions

    International Nuclear Information System (INIS)

    Suraud, E.; Schuck, P.

    1988-07-01

    A detailed study of the excitation of giant dipole modes (GDR) in intermediate energy heavy-ion collisions is presented in the framework of a full (non linearized) Landau-Vlasov equation. After having recalled the basic inputs of this dynamical formalism, within insisting upon the limitations of the Uehling-Uhlenbeck collision integral and upon the introduction of a realistic (isospin dependant) effective interaction, we present our tools for analysing the GDR in the simple case of isolated nuclei. We then pass on to simulations of collisions and discuss in some detail isospin modes in the model 12 Be + 12 C reaction. Results obtained for the energy of the excited dipole mode are in agreement with what is expected for excited, rotating, giant dipole oscillations in deformed nuclei

  3. A sum rule description of giant resonances at finite temperature

    International Nuclear Information System (INIS)

    Meyer, J.; Quentin, P.; Brack, M.

    1983-01-01

    A generalization of the sum rule approach to collective motion at finite temperature is presented. The m 1 and msub(-1) sum rules for the isovector dipole and the isoscalar monopole electric modes have been evaluated with the modified SkM force for the 208 Pb nucleus. The variation of the resulting giant resonance energies with temperature is discussed. (orig.)

  4. Giant first-forbidden resonances

    International Nuclear Information System (INIS)

    Krmpotic, F.; Nakayama, K.; Sao Paulo Univ.; Pio Galeao, A.; Sao Paulo Univ.

    1983-01-01

    Recent experimental data on first-forbidden charge-exchange resonances are discussed in the framework of a schematic model. We also evaluate the screening of the weak coupling constants induced by both the giant resonances and the δ-isobar. It is shown that the last effect does not depend on the multipolarity of the one-particle moment. Due to the same reason, the fraction of the reaction strength pushed up into the δ-resonance region is always the same regardless of the quantum numbers carried by the excitation. Simple expressions are derived for the dependence of the excitation energies of the first-forbidden giant resonances on the mass number and isospin of the target. The model reproduces consistently both the Gamow-Teller and the first-forbidden resonances. (orig.)

  5. Giant resonances: reaction theory approach

    International Nuclear Information System (INIS)

    Toledo Piza, A.F.R. de; Foglia, G.A.

    1989-09-01

    The study of giant resonances through the use of reaction theory approach is presented and discussed. Measurements of cross-sections to the many available decay channels following excitation of giant multipole resonances (GMR) led one to view these phenomena as complicated dynamical syndromes so that theoretical requirements for their study must be extended beyond the traditional bounds of nuclear structure models. The spectra of decay products following GMR excitation in heavy nuclei are well described by statistical model (Hauser-Feshback, HF) predictions indicated that spreading of the collective modes plays a major role in shaping exclusive cross-sections. (A.C.A.S.) [pt

  6. Excitation of giant resonances in heavy ion collisions

    International Nuclear Information System (INIS)

    Kuehn, W.

    1991-01-01

    Introduction: What are Giant Resonances? General Features of Giant Resonances, Macroscopic Description and Classification, Basic Excitation Mechanisms, Decay Modes, Giant Resonances Built on Excited States, Relativistic Coulomb Excitation of Giant Resonances, Experimental Situation. (orig.)

  7. Giant multipole resonances: perspectives after ten years

    International Nuclear Information System (INIS)

    Bertrand, F.E.

    1980-01-01

    Nearly ten years ago evidence was published for the first of the so-called giant multipole resonances, the giant quadrupole resonance. During the ensuing years research in this field has spread to many nuclear physics laboratories throughout the world. The present status of electric giant multipole resonances is reviewed. 24 figures, 1 table

  8. Giant resonances on excited states

    International Nuclear Information System (INIS)

    Besold, W.; Reinhard, P.G.; Toepffer, C.

    1984-01-01

    We derive modified RPA equations for small vibrations about excited states. The temperature dependence of collective excitations is examined. The formalism is applied to the ground state and the first excited state of 90 Zr in order to confirm a hypothesis which states that not only the ground state but every excited state of a nucleus has a giant resonance built upon it. (orig.)

  9. Isotopic dependence of the giant quadrupole resonance in the stable even-mass molybdenum nuclei

    International Nuclear Information System (INIS)

    Moalem, A.; Gaillard, Y.; Bemolle, A.M.; Buenerd, M.; Chauvin, J.; Duhamel, G.; Lebrun, D.; Martin, P.; Perrin, G.; de Saintignon, P.

    1979-01-01

    Inelastic scattering of 110 MeV 3 He particles is used to probe the quadrupole strength in the even Mo isotopes. The peak position of the giant quadrupole resonance is found to decrease more rapidly than predicted by the A/sup -1/3/ law, a behavior very similar to that exhibited by the photonuclear giant dipole resonance. The width and strength of the giant quadrupole resonance are practically constant in 92 Mo through 100 Mo

  10. Determination of giant resonance strengths

    International Nuclear Information System (INIS)

    Serr, F.E.

    1983-01-01

    Using theoretical strength functions to describe the different giant resonances expected at excitation energies of the order of (60-85)/Asup(1/3) MeV, we calculate the double differential cross sections d 2 sigma/dΩ dE associated with the reactions 208 Pb(α, α') and 90 Zr(α, α') (Esub(α) = 152 MeV). The angular distributions for the giant quadrupole and giant monopole resonances obtained from fits to these spectra, making simple, commonly used assumptions for the peak shapes and background, are compared to the original angular distributions. The differences between them are an indication of some of the uncertainties affecting the giant resonance strengths extracted from hadron inelastic scattering data. Fits to limited angular regions lead to errors of up to 50% in the value of the energy-weighted sum rule, depending on the angles examined. While it seems possible to extract the correct EWSR for the GMR by carrying out the analyses at 0 0 , no single privileged angle seems to exist in the case of the GQR. (orig.)

  11. Excitation of giant monopole and quadrupole resonances

    Energy Technology Data Exchange (ETDEWEB)

    Ogata, H. [Osaka Univ., Suita (Japan). Research Center for Nuclear Physics; Yamagata, T.; Tanaka, M. [and others; Ikegami, H.; Muraoka, M. [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

    1980-01-01

    Recent studies on the giant monopole resonance (GMR) and the giant quadrupole resonance (GQR) in /sup 144/Sm and /sup 208/Pb using the ..cap alpha..-scattering performed at RCNP are summarized. The observed angular range covered 1.6/sup 0/ -- 7/sup 0/ with a coupled system of a dipole and a triplet quadrupole magnet. The incident energy was changed from 84 to 119 MeV. The resonance shapes and energy-weighted sum-rule strengths of the GMR and the GQR were reliably deduced as a function of incident energy. The quadrupole strength of --20% was found in the GMR region. The observed excitation function of the GMR was compared with the DWBA calculation, in which the Satchler's Version I was used as a form factor representing the compressional motion of the nucleus. It was found that the experimental excitation function of the GMR shows steeper decrease as lowering the incident energy than the DWBA prediction whereas that of the GQR is successfully described by the DWBA. This suggests that examination of the model describing the GMR is necessary.

  12. Features of the giant E1 resonance

    International Nuclear Information System (INIS)

    Bergere, R.

    1976-01-01

    Since most of the available experimental data concerning the giant dipole E1 resonance (GDR) have been obtained with real photons, the characteristics of real photon sources are reviewed with an attempt to connect the experimental particularities of each of them to the specific parameters of the GDR which it is best suited to reach. Some systematic properties gathered from experimental data of GDR (average energy, splitting and broadening of the GDR) are compared with the predictions of the static and dynamic collective models of the nuclei. The position in energy and the fine structure of the GDR are more closely connected to shell model predictions as nuclei get lighter, the various experimental integrated cross sections being also more easily understood by comparisons with microscopic models. Most of the reported data refer to the doorway state through which GDR is excited, however the competition between the decay channels for GDR states is also emphasized

  13. Giant multipole resonances: an experimental review

    International Nuclear Information System (INIS)

    Bertrand, F.E.

    1979-01-01

    During the past several years experimental evidence has been published for the existance of nondipole giant resonances. These giant multipole resonances, the so-called new giant resonances were first observed through inelastic hadron and electron scattering and such measurements have continued to provide most of the information in this field. A summary is provided of the experimental evidence for these new resonances. The discussion deals only with results from inelastic scattering and only with the electric multipoles. Emphasis is placed on the recent observations of the giant monopole resonance. Results from recent heavy-ion and pion inelastic scattering are discussed. 38 references

  14. Spectral structure of the pygmy dipole resonance.

    Science.gov (United States)

    Tonchev, A P; Hammond, S L; Kelley, J H; Kwan, E; Lenske, H; Rusev, G; Tornow, W; Tsoneva, N

    2010-02-19

    High-sensitivity studies of E1 and M1 transitions observed in the reaction 138Ba(gamma,gamma{'}) at energies below the one-neutron separation energy have been performed using the nearly monoenergetic and 100% linearly polarized photon beams of the HIgammaS facility. The electric dipole character of the so-called "pygmy" dipole resonance was experimentally verified for excitations from 4.0 to 8.6 MeV. The fine structure of the M1 "spin-flip" mode was observed for the first time in N=82 nuclei.

  15. Description of the giant dipole mode in states of high angular momentum

    International Nuclear Information System (INIS)

    Hilton, R.R.

    1982-01-01

    The effects of the Coriolis interaction on the giant dipole mode is discussed within the framework of a cranked deformed oscillator in which dipole-dipole two body forces are taken into account. Energy splittings of the dipole mode in addition to those attributable to the shape are found. (orig.)

  16. Recent Results From Skyrme-TDHF: Giant Resonances and Collisions

    International Nuclear Information System (INIS)

    Stevenson, Paul D.

    2007-01-01

    Using fully three-dimensional Time-Dependent Hartree-Fock with Skyrme forces allows one to explore small and large amplitude collective motion in nuclei using only an effective interaction fitted to ground state and nuclear matter properties as input. In this talk, results are presented for TDHF calculations of giant resonances and nuclear collisions. We examine deformation splitting of the giant dipole resonance on ground and excited intrinsic superdeformed states, showing the interplay between Landau splitting and deformation splitting, including effects of triaxiality[1]. In the case of giant monopole resonances, isospin-mixing is examined, showing that the isovector and isoscalar parts of strength functions are strongly coupled [2]. The role of absorption in the TDHF approach to linear and nonlinear regimes is examined[3]. Calculations of nuclear collisions are also explored, showing that the effects of fully relaxed symmetry produce new modes of energy loss not found in previous calculations [4]. (Author)

  17. Coupled-resonator waveguide perfect transport single-photon by interatomic dipole-dipole interaction

    Science.gov (United States)

    Yan, Guo-an; Lu, Hua; Qiao, Hao-xue; Chen, Ai-xi; Wu, Wan-qing

    2018-06-01

    We theoretically investigate single-photon coherent transport in a one-dimensional coupled-resonator waveguide coupled to two quantum emitters with dipole-dipole interactions. The numerical simulations demonstrate that the transmission spectrum of the photon depends on the two atoms dipole-dipole interactions and the photon-atom couplings. The dipole-dipole interactions may change the dip positions in the spectra and the coupling strength may broaden the frequency band width in the transmission spectrum. We further demonstrate that the typical transmission spectra split into two dips due to the dipole-dipole interactions. This phenomenon may be used to manufacture new quantum waveguide devices.

  18. Excitation and photon decay of giant resonances excited by intermediate energy heavy ions

    International Nuclear Information System (INIS)

    Bertrand, F.E.; Beene, J.R.

    1987-01-01

    Inelastic scattering of medium energy heavy ions provides very large cross sections and peak-to-continuum ratios for excitation of giant resonances. For energies above about 50 MeV/nucleon, giant resonances are excited primarily through Coulomb excitation, which is indifferent to isospin, thus providing a good probe for the study of isovector giant resonances. The extremely large cross sections available from heavy ion excitation permit the study of rare decay modes of the giant resonances. In particular, recent measurements have been made of the photon decay of giant resonances following excitation by 22 and 84 MeV/nucleon 17 O projectiles. The singles results at 84 MeV/nucleon yield peak cross sections for the isoscalar giant quadrupole resonance and the isovector giant dipole resonance of approximately 0.8 and 3 barns/sr, respectively. Data on the ground state decay of the isoscalar giant quadrupole and isovector giant dipole resonances are presented and compared with calculations. Decays to low-lying excited states are also discussed. Preliminary results from an experiment to isolate the 208 Pb isovector quadrupole resonance using its gamma decay are presented. 22 refs., 19 figs., 1 tab

  19. Giant resonances in heavy-ion reactions

    International Nuclear Information System (INIS)

    Hussein, M.S.

    1982-11-01

    The several roles of multipole giant resonances in heavy-ion reactions are discussed. In particular, the modifications in the effective ion-ion potencial due to the virtual excitation of giant resonances at low energies, are considered and estimated for several systems. Real excitation of giant resonances in heavy-ion reactions at intermediate energies are then discussed and their importance in the approach phase of deeply inelastic processes in emphasized. Several demonstrative examples are given. (Author) [pt

  20. The pygmy dipole resonance in neutron-rich nuclei

    International Nuclear Information System (INIS)

    Hung, Nguyen Quang; Kiet, Hoang Anh Tuan; Duc, Huynh Ngoc; Chuong, Nguyen Thi

    2016-01-01

    The pygmy dipole resonance (PDR), which has been observed via the enhancement of the electric dipole strength E 1 of atomic nuclei, is studied within a microscopic collective model. The latter employs the Hartree-Fock (HF) method with effective nucleon-nucleon interactions of the Skyrme types plus the random-phase approximation (RPA). The results of the calculations obtained for various even-even nuclei such as "1"6"-"2"8O, "4"0"-"5"8Ca, "1"0"0"-"1"2"0Sn, and "1"8"2"-"2"1"8Pb show that the PDR is significantly enhanced when the number of neutrons outside the stable core of the nucleus is increased, that is, in the neutron-rich nuclei. As the result, the relative ratio between the energy weighted sum of the strength of the PDR and that of the GDR (giant dipole resonance) does not exceed 4%. The collectivity of the PDR and GDR states will be also discussed. (paper)

  1. Electromagnetic decay of giant resonances

    International Nuclear Information System (INIS)

    Beene, J.R.; Bertrand, F.E.; Halbert, M.L.; Auble, R.L.; Hensley, D.C.; Horen, D.J.; Robinson, R.L.; Sayer, R.O.; Sjoreen, T.P.

    1985-01-01

    Coincidence experiments were done to investigate the photon and neutron emission from the giant resonance regions of 208 Pb and 90 Zr using the ORNL Spin Spectrometer, a 72-segment NaI detector system. We have determined the total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying states as a function of excitation energy in 208 Pb to approx.15 MeV. Similar data were also obtained on 90 Zr. The total yield of ground-state E2 gamma radiation in 208 Pb and the comparative absence of such radiation in 90 Zr can only be understood if decay of compound (damped) states is considered. Other observations in 208 Pb include the absence of a significant branch from the giant quadrupole resonance (GQR) to the 3 - state at 2.6 MeV, a strong branch to a 3 - state at 4.97 MeV from the same region, and transitions to various 1 - states between 5 to 7 MeV from the E* approx. 14 MeV region (EO resonance)

  2. Electromagnetic decay of giant resonances

    International Nuclear Information System (INIS)

    Beene, J.R.; Bertrand, F.E.; Halbert, M.L.; Auble, R.L.; Hensley, D.C.; Horen, D.J.; Robinson, R.L.; Sayer, R.O.; Sjoreen, T.P.

    1985-01-01

    Coincidence experiments are carried out to investigate the photon and neutron emission from the giant resonance regions of 208 Pb and 90 Zr using the ORNL Spin Spectrometer, a 72-segment NaI detector system. The authors determined the total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying states as a function of excitation energy in 208 Pb to ∼15 MeV. Similar data were also obtained on 90 Zr. The total yield of ground-state E2 gamma radiation in 208 Pb and the comparative absence of such radiation in 90 Zr can only be understood if decay of compound (damped) states is considered. (Auth.)

  3. Dipole and quadrupole magnetic resonances in nuclei of Ni isotopes

    International Nuclear Information System (INIS)

    Goncharova, N.G.; Mishchenko, G.M.; Ehramzhyan, R.A.

    1982-01-01

    Basing on a microscopic approach to the nuclear shell model, magnetic resonances following the electron excitation of the 58 Ni and 60 Ni nuclei are considered. 0h/2π#betta# and 2h/2π#betta#-transitions are taken into accoun for the M1-excitations. For the M2-states, transitions to the next shell are considered only. For the magnetic excitations the form factors and electron-excitation cross sections are calculated, and the effect of the lower 2 1+ , 2 2+ , 3 - , 4 + phonon excitations on the position and structure of the M1- and M2-resonances is traced. +he energies and mean equilibrium deformations are presented for the phonons taken into account. The structure and position of the main magnetic resonance maxima, in difference with the giant dipole resonance in photoabsorption, have proven to be weakly dependent on the isotope choice. For the M1-resonance this effect is related with the fact that the lower excitation states, located in the energy range E 60 Ni and 58 Ni, respectively. A strongly collectivized state, acquiring a notable strength of the M-1 transitions, is located at approximately 32 MeV. The form factor for this level attains the maximum at q=160-190 MeV/c

  4. Statistical contribution in the giant multipolar resonance decay in hevay nuclei

    International Nuclear Information System (INIS)

    Teruya, N.

    1986-01-01

    Statistical calculations are made for the decay in the electric monopole giant resonance in 208 Pb and electric dipole giant resonance in 209 Bi, using the Hauser-Feshbach formalism. Calculations are done using the experimental energy levels of the corresponding residual nuclei. The particle-vibrator model is used for those experimental levels without spin and parity determination. The influence of different parametrizations of the optical potential in the statistical calculation result is also studied. (L.C.) [pt

  5. Static electromagnetic properties of giant resonances

    International Nuclear Information System (INIS)

    Koo, W.K.

    1986-03-01

    Static electric monopole and quadrupole matrix elements, which are related to the mean square radius and quadrupole moment respectively, are derived for giant resonances of arbitrary multipolarity. The results furnish information on the size and shape of the nucleus in the excited giant states. (author)

  6. Decay properties of the Pygmy dipole resonance

    Energy Technology Data Exchange (ETDEWEB)

    Isaak, J.; Savran, D.; Silva, J. [EMMI, Darmstadt (Germany); FIAS, Frankfurt (Germany); Aumann, T.; Loeher, B. [IKP, TU Darmstadt (Germany); GSI, Darmstadt (Germany); Beck, T.; Gayer, U.; Pietralla, N.; Romig, C.; Scheit, H.; Werner, V.; Zweidinger, M. [IKP, TU Darmstadt (Germany); Cooper, N. [WNSL, Yale University, New Haven (United States); Derya, V.; Zilges, A. [IKP, Universitaet zu Koeln (Germany); Kelley, J. [Department of Physics, Duke University, TUNL (United States); Department of Physics, NCSU (United States); Scheck, M. [School of Engineering, UWS, Paisley (United Kingdom); SUPA, Glasgow (United Kingdom); Tornow, W.; Weller, H. [Department of Physics, Duke University, TUNL (United States)

    2015-07-01

    The so-called Pygmy Dipole Resonance (PDR) has been investigated in stable and in a few unstable nuclei in the past decades. So far, decay properties have been determined only in an indirect or model-dependent way. An excellent tool to extend the study of the decay pattern of the PDR is provided by the γ{sup 3}-setup at the High Intensity γ-ray Source (HIγS). The combination of the γ-γ-coincidence method and the quasi-monochromatic photon beam at HIγS allows to observe primary transitions directly with high sensitivity and to obtain information on the decay behavior of individual states as well as extracting averaged quantities in a model-independent way. Recent experimental results for nuclei in the Z=50 and N=82 mass region are presented.

  7. Fission decay properties of nuclear giant multipole resonances

    International Nuclear Information System (INIS)

    Dias, H.; Arruda Neto, J.D.T.; Hussein, M.S.; Carlson, B.V.

    1986-05-01

    The statistical fission decay properties of the giant dipole, quadrupole and monopole resonances in 236 U are investigated with the aid of the Hauser-Feshbach model. It is found, contrary to several recent claims, that the GQR fission decay probability is as large as that of the GDR, at energies higher than the fission barrier. At energies close to the f.b., the GQR fission probability is found to be appreciably larger than that of the GDR. The GMR fission probability follows closely that of the GQR. (Author) [pt

  8. The giant resonances in hot nuclei. Linear response calculations

    International Nuclear Information System (INIS)

    Braghin, F.L.; Vautherin, D.; Abada, A.

    1995-01-01

    The isovector response function of hot nuclear matter is calculated using various effective Skyrme interactions. For Skyrme forces with a small effective mass the strength distribution is found to be nearly independent of temperature, and shows little collective effects. In contrast effective forces with an effective mass close to unity produce at zero temperature sizeable collective effects which disappear at temperatures of a few MeV. The relevance of these results for the saturation of the multiplicity of photons emitted by the giant dipole resonance in hot nuclei observed in recent experiments beyond T = 3 MeV is discussed. (authors). 12 refs., 3 figs

  9. Two-phonon giant resonances in 136Xe, 208Pb, and 238U

    International Nuclear Information System (INIS)

    Boretzky, K.; Gruenschloss, A.; Ilievski, S.; Adrich, P.; Aumann, T.; Bertulani, C.A.; Cub, J.; Dostal, W.; Eberlein, B.; Elze, T.W.; Emling, H.; Fallot, M.; Holeczek, J.; Holzmann, R.; Kozhuharov, C.; Kratz, J.V.; Kulessa, R.; Leifels, Y.; Leistenschneider, A.; Lubkiewicz, E.; Mordechai, S.; Ohtsuki, T.; Reiter, P.; Simon, H.; Stelzer, K.; Stroth, J.; Suemmerer, K.; Surowiec, A.; Wajda, E.; Walus, W.

    2003-07-01

    The excitation of the double-phonon giant dipole resonance was observed in heavy projectile nuclei impinging on targets of high nuclear charge with energies of 500-700 MeV/nucleon. New experimental data are presented for 136 Xe and 238 U together with further analysis of earlier data on 208 Pb. Differential cross sections dσ/dE * and dσ/dθ for electromagnetic excitations were deduced. Depending on the isotope, cross sections appear to be enhanced in comparison to those expected from a purely harmonic nuclear dipole response. The cumulative effect of excitations of two-phonon states composed of one dipole and one quadrupole phonon, of predicted anharmoniticies in the double-phonon dipole response, and of damping of the dipole resonance during the collision may account for the discrepancy. In addition, decay properties of two-phonon resonances were studied and compared to that of a statistical decay. (orig.)

  10. Looking inside giant resonance fine structure

    International Nuclear Information System (INIS)

    Ponomarev, V.Yu.; Voronov, V.V.

    1993-01-01

    Microscopic calculations of the fine structure of giant resonances for spherical nuclei are presented. Excited states are treated by wave function which takes into account coupling of simple one-phonon configurations with more complex ones. Nuclear structure calculations are applied to the description of the γ-decay of resonances into the ground and low-lying excited states. 16 refs.; 4 figs

  11. Collective motion and giant resonances

    International Nuclear Information System (INIS)

    Wilhelmi, Z.; Kicinska-Habior, M.

    1984-01-01

    The report contains 15 papers devoted to problems of giant collective excitations of nuclei, heavy-ion induced reactions and their bearing on various aspects of nuclear structure. In some of them the numerical data are given. (A.S.)

  12. Electron inelastic scattering by compound nuclei and giant multipole resonances

    International Nuclear Information System (INIS)

    Dzhavadov, A.V.; Mukhtarov, A.I.; Mirabutalybov, M.M.

    1980-01-01

    Multipole giant resonances in heavy nuclei have been investigated with the application of the Danos-Greiner dynamic collective theory to the Tassi model. The monopole giant resonance has been studied in 158 Gd, 166 Er, 184 W, 232 Th and 238 V nuclei at the incident electron energy E=200 MeV. Dependences of the form factor square of electron scattering by a 166 Er nucleus on the scattering angle obtained in the distorted-wave high-energy approximation (DWHEA) are presented. Giant dipole and quadrupole resonances in 60 Ni and 90 Zr nuclei have been studied. A comparison has been made of theoretical results obtained in the DWHEA for the dependence of the form factor square on the effective momentum transfer with the experimental data. The analysis of the obtained results led to the following conclusions. To draw a conclusion about the validity of one or another nuclear model and methods for calculating form factors, it is necessary to investigate, both theoretically and experimentally, electron scattering at great angles (THETA>=70 deg). To obtain a good agreement it is necessary to take account of the actual proton and neutron distributions in the ground state and their dynamic properties in an excited state [ru

  13. Structure of the pygmy dipole resonance in Sn-124

    NARCIS (Netherlands)

    Endres, J.; Savran, D.; Butler, P. A.; Harakeh, M. N.; Harissopulos, S.; Herzberg, R. -D.; Kruecken, R.; Lagoyannis, A.; Litvinova, E.; Pietralla, N.; Ponomarev, V. Yu.; Popescu, L.; Ring, P.; Scheck, M.; Schlueter, F.; Sonnabend, K.; Stoica, V. I.; Zilges, A.; Wortche, Heinrich

    2012-01-01

    Background: In atomic nuclei, a concentration of electric dipole strength around the particle threshold, commonly denoted as pygmy dipole resonance, may have a significant impact on nuclear structure properties and astrophysical scenarios. A clear identification of these states and the structure of

  14. Electroexcitation of giant multipole resonances in 208Pb

    International Nuclear Information System (INIS)

    Sasao, M.; Torizuka, Y.

    1977-01-01

    Electroexcitation of the nuclear continuum for 208 Pb at excitation energies up to 100 MeV has been measured at momentum transfers in the range from 0.45 to 1.2 fm -1 . Unfolding of the radiation tail was performed using a tail function which takes into account the multiple-photon emission effect. The spectra at these momentum transfers deviate significantly from the prediction of the Fermi-gas model but are consistent with the sum of the multipole strengths of the random-phase approximation; the excess cross section on the low excitation energy side indicates the excitation of multipole resonances. A series of 208 Pb spectra at low momentum transfers was expanded into E1, E2 (E0), E3, and higher multipole components using the q dependence of the Tassie model for isoscalar modes and the Goldhaber-Teller or Steinwedel-Jensen model for isovector modes. The giant dipole resonance thus obtained is consistent with that from photoreactions. Isoscalar and isovector giant quadrupole resonances are seen, respectively, at 11 and 22.5 MeV and an octupole resonance at 16 MeV. A monopole resonance is suggested at 13.5 MeV. The reduced 2 > 2 , B (E1), B (E2), and B (E3) consume most of the corresponding energy weighted sum rule if the q dependences of the Tassie and Goldhaber-Teller models are assumed. The results with these models are consistent with the random-phase approximation

  15. Isovector giant quadrupole resonance in 63Cu

    International Nuclear Information System (INIS)

    Wolynec, E.; Pastura, V.F.S.; Martins, M.N.

    1988-01-01

    The decay of the isovector E2 giant resonance in 63 Cu has been studied by measuring the (e,2n) cross section, in the incident electron energy range 22-45 MeV. The photodisintegration induced by bremsstrahlung was also measured. The electrodisintegration results have been analyzed using the distorted wave Born approximation E1 and E2 virtual photon spectra to obtain these multipole components in the corresponding (γ,2n) cross section. It is found that the isovector E2 giant resonance decays dominantly by two-neutron emission in 63 Cu. This decay channel exhausts 65 percent of the energy weighted E2 sum. (author0 [pt

  16. Macroscopic description of isoscalar giant multipole resonances

    International Nuclear Information System (INIS)

    Nix, J.R.; Sierk, A.J.

    1980-01-01

    On the basis of a simple macroscopic model, we calculate the isoscalar giant-resonance energy as a function of mass number and multipole degree. The restoring force is determined from the distortion of the Fermi surface, and the inertia is determined for the incompressible, irrotational flow of nucleons with unit effective mass. With no adjustable parameters, the resulting closed expression reproduces correctly the available experimental data, namely the magnitude and dependence upon mass number of the giant quadrupole energy and the magnitude of the giant octupole energy for 208 Pb. We also calculate the isoscalar giant-resonance width as a function of mass number and multipole degree for various macroscopic damping mechanisms, including two-body viscosity, one-body dissipation, and modified one-body dissipation. None of these damping mechanisms reproduces correctly all features of the available experimental data, namely the magnitude and dependence upon mass number of the giant quadrupole width and the magnitude of the giant octupole width for 208 Pb

  17. Nonperturbative study of the damping of giant resonances in hot nuclei

    International Nuclear Information System (INIS)

    De Blasio, F.V.; Cassing, W.; Tohyama, M.; Bortignon, P.F.; Broglia, R.A.

    1992-01-01

    The damping of dipole and quadrupole motion in 16 O and 40 Ca at zero and finite temperature is studied including particle-particle and particle-hole interactions to all orders of perturbation. We find that the dipole dynamics in these light nuclei is well described in terms of mean-field theory (time-dependent Hartree-Fock), while the quadrupole motion is strongly damped through the coupling to more complicated configurations. Both the centroid and the damping width of the quadrupole and dipole giant resonances show a clear stability with temperature as a consequence of the weakening of the interaction, which contrasts with the increase of the phase space

  18. Study of giant resonances with pions

    International Nuclear Information System (INIS)

    Baer, H.W.

    1984-01-01

    Recent results on giant resonances obtained with pion-inelastic scattering and with single- and double-charge-exchange scattering are reviewed. The states discussed are isobaric analog states, double-isobaric analog states, and isovector L = 0, 1, and 2 collective states. 36 references

  19. Giant resonances in the deformed continuum

    International Nuclear Information System (INIS)

    Nakatsukasa, T.; Yabana, K.

    2004-01-01

    Giant resonances in the continuum for deformed nuclei are studied with the time-dependent Hartree-Fock (TDHF) theory in real time and real space. The continuum effect is effectively taken into account by introducing a complex Absorbing Boundary Condition (ABC). (orig.)

  20. The Droplet model of the Giant Fipole Resonance

    International Nuclear Information System (INIS)

    Myers, W.D.; Kodama, T.; El-Jaick, L.J.; Hilf, E.R.

    1976-10-01

    The nuclear Giant Dipole Resonance (GDR) energies are calculated using a macroscopic hydronamical model with two new features. The motion is treated as a combination of the usual Goldhaber-Teller (GT) and Steinwedel-Jensen (SJ) modes, and the restoring forces are all calculated using the Droplet Model. The A dependence of the resonance energies is well reproduced without any adjustable parameters, and the measured magnitude of the energies serves to fix the value of the effective mass m* used in the theory. The GDR is found to consist mainly of a GT-type motion with the SJ-mode becoming more important for heavy nuclei. The width P of the GDR is also estimated on the basis of an expression for one-body damping [pt

  1. Dipole resonances in light neutron-rich nuclei studied with time-dependent calculations of antisymmetrized molecular dynamics

    International Nuclear Information System (INIS)

    Kanada-En'yo, Y.; Kimura, M.

    2005-01-01

    To study isovector dipole responses of neutron-rich nuclei, we applied a time-dependent method of antisymmetrized molecular dynamics. The dipole resonances in Be, B, and C isotopes were investigated. In 10 Be, 15 B, and 16 C, collective modes of the vibration between a core and valence neutrons cause soft resonances at the excitation energy E x =10-15 MeV below the giant dipole resonance (GDR). In 16 C, we found that a remarkable peak at E x =14 MeV corresponds to the coherent motion of four valence neutrons against a 12 C core, whereas the GDR arises in the E x >20 MeV region because of vibration within the core. In 17 B and 18 C, the dipole strengths in the low-energy region decline compared with those in 15 B and 16 C. We also discuss the energy-weighted sum rule for the E1 transitions

  2. Double giant resonances in time-dependent relativistic mean-field theory

    International Nuclear Information System (INIS)

    Ring, P.; Podobnik, B.

    1996-01-01

    Collective vibrations in spherical nuclei are described in the framework of time-dependent relativistic mean-field theory (RMFT). Isoscalar quadrupole and isovector dipole oscillations that correspond to giant resonances are studied, and possible excitations of higher modes are investigated. We find evidence for modes which can be interpreted as double resonances. In a quantized RMFT they correspond to two-phonon states. (orig.)

  3. Resonances and dipole moments in dielectric, magnetic, and magnetodielectric cylinders

    DEFF Research Database (Denmark)

    Dirksen, A.; Arslanagic, Samel; Breinbjerg, Olav

    2011-01-01

    An eigenfunction solution to the problem of plane wave scattering by dielectric, magnetic, and magnetodielectric cylinders is used for a systematic investigation of their resonances. An overview of the resonances with electric and magnetic dipole moments, needed in, e.g., the synthesis...

  4. Triple Giant Resonance Excitations: A Microscopic Approach

    International Nuclear Information System (INIS)

    Lanza, E.G.; Andres, M.V.; Catara, F.; Chomaz, Ph.; Fallot, M.; Scarpaci, J.A.

    2007-01-01

    We present, for the first time, microscopic calculations of inelastic cross sections of the triple excitation of giant resonances induced by heavy ion probes. We start from a microscopic approach based on RPA. The mixing of three-phonon states among themselves and with two- and one-phonon states is considered within a boson expansion with Pauli corrections. In this way we go beyond the standard harmonic approximations and get anharmonic excitation spectra. At the same time we also introduce non-linearities in the external field. The calculations are done by solving semiclassical coupled channel equations, the channels being superpositions of one-, two- and three-phonon states. Previous calculations for the Double Giant Resonance excitation show good agreement with experimental cross sections. The inclusion of the three phonon components confirms the previous results for the DGR and produces a strong increase in the Triple GR energy region

  5. Giant resonance effects in radiative capture

    International Nuclear Information System (INIS)

    Snover, K.A.

    1979-01-01

    The technique of capture reaction studies of giant resonance properties is described, and a number of examples are given. Most of the recent work of interest has been in proton capture, in part because of the great utility (and availability) of polarized beams; most of the discussion concerns this reaction. Alpha capture, which has been a useful tool for exploring isoscalar E2 strength, and neutron capture are, however, also treated. 46 references, 14 figures

  6. Electron scattering studies of selected electric and magnetic dipole and quadrupole transitions in light and heavy nuclei, the new multipole giant resonances and atomic transitions - recent results from the DALINAC

    International Nuclear Information System (INIS)

    Richter, A.

    1977-01-01

    Recent experimental work from the Darmstadt electron linear accelerator (DALINAC) is briefly summarized. Particular emphasis is given to the following topics: high resolution inelastic electron scattering (ΔE approximately 30 keV FWHM) has been used to study the radiative width and magnetization density of the 2 + , T = 1 state at 16.11 MeV in 12 C, E2 strength distribution in 28 Si below an excitation energy of 13 MeV and the isospin forbidden E1 electroexcitation of the 1 - , T = 0 state at 6.95 MeV in 40 Ca. High resolution inelastic electron scattering was also employed to determine certain M1 transitions in 14 N, 28 Si, 39 K, 58 Ni, 90 Zr and 208 Pb and the M2 strength distribution in the two heaviest nuclei. At medium energy resolution (ΔE approximately 200 keV FWHM) spectra at various angles and bombarding energies have been measured from (4-31) MeV for 208 Pb. They are being analyzed in order to determine E0, E1, E2, E3 and M1 giant resonance strength in the continuum. The Z and E dependence and the scaling behaviour of the atomic inner shell ionization cross section at relativistic electron impact is studied on gaseous and solid targets. (orig./BJ) [de

  7. The giant resonance and the shape of hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Bracco, A; Camera, F; Million, B; Pignanelli, M [Milan Univ. (Italy). Ist. di Fisica; Gaardhoje, J J; Maj, A; Atac, A [Niels Bohr Inst., Copenhagen (Denmark)

    1992-08-01

    The gamma decay of the giant dipole resonance is a sensitive tool for investigating how nuclear shape changes with spin and excitation energy, but the information is coded in a subtle way, inasmuch as the shape and orientation of nuclei at finite temperature display large fluctuations. At the time of the conference, the three systems {sup 109-110}Sn, {sup 161-162}Yb and {sup 165-167}Er had recently been studied on the HECTOR spectrometer. The Sn nuclei are spherical in their ground states, and are expected to become oblate under the stress of rotation. The Yb and Er nuclei are prolate, and are expected to become first spherical, then oblate. While the patterns of the measured angular anisotropies are consistent with this general picture, many questions still remain open. 3 refs., 1 tab., 3 figs.

  8. Decay of the giant monopole resonance in heavy nuclei

    International Nuclear Information System (INIS)

    Brandenburg, S.

    1985-01-01

    In this thesis an experimental study of the properties of the giant monopole resonance (GMR) in nuclei is described. The main subject is the study of the neutron decay of the GMR in 208 Pb, and the fission decay of the GMR in 238 U. Furthermore the strength distribution and decay properties of the monopole strength in 24 Mg and 40 Ca were studied. The strength distribution of the isoscalar monopole (and also of the isoscalar dipole) strength as obtained from the angular distribution of the excited strength at small scattering angles are discussed. For the excitation of the GMR inelastic scattering at very small scattering angles, including 0 0 , of 120 MeV α-particles was employed. The experimental technique for performing this type of measurements at the KVI was developed in the course of this study and is the subject of a separate chapter. (Auth.)

  9. ZZ-CENPL, Chinese Evaluated Nuclear Parameter Library. ZZ CENPL-DLS, Discrete Level Schemes and Gamma Branching Ratios Library; ZZ CENPL-FBP, Fission Barrier Parameter Library; ZZ CENPL-GDRP, Giant Dipole Resonance Parameter Library; ZZ CENPL-NLD, Nuclear Level Density Parameter Library; ZZ CENPL-MCC, Nuclear Ground State Atomic Masses Library; ZZ CENPL-OMP, Optical Model Parameter Library

    International Nuclear Information System (INIS)

    Su Zongdi

    1995-01-01

    Description of program or function: CENPL - GDRP (Giant Dipole Resonance Parameters for Gamma-Ray): - Format: special format described in documentation; - Nuclides: V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, I, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Er, Lu, Ta, W, Re, Os, Ir, Pt, Au, Hg, Pb, Bi, Th, U, Np, Pu. - Origin: Experimental values offered by S.S. Dietrich and B.L. Berman. CENPL - FBP (Fission Barrier Parameter Sub-Library): - Format: special format described in documentation; - Nuclides: (1) 51 nuclei region from Th-230 to Cf-255, (2) 46 nuclei region from Th-229 to Cf-253, (3) 24 nuclei region from Pa-232 to Cf-253; - Origin: (1) Lynn, (2) Analysis of experimental data by Back et al., (3) Ohsawa. CENPL - DLS (Discrete level scheme and branch ratio of gamma decay: - Format: Special format described in documentation; - Origin: ENSDF - BNL. CENPL - NLD (Nuclear Level Density): - Format: Special format described in documentation; - Origin: Huang Zhongfu et al. CENPL - OMP (Optical model parameter sub-library): - Format: special format described in documentation ; - Origin: CENDL, ENDF/B-VI, JENDL-3. CENPL - MC (I) and (II) (Atomic masses and characteristic constants for nuclear ground states) : - Format: Brief table format; - Nuclides: 4760 nuclides ranging from Z=0 A=1 to Z=122 A=318. - Origin: Experimental data and systematic results evaluated by Wapstra, theoretical results calculated by Moller, ENSDF - BNL and Nuclear Wallet Cards. CENPL contains the following six sub-libraries: 1. Atomic Masses and Characteristic Constants for nuclear ground states (MCC). This data consists of calculated and in most cases also measured mass excesses, atomic masses, total binding energies, spins, parities, and half-lives of nuclear ground states, abundances, etc. for 4800 nuclides. 2. Discrete Level Schemes and branching ratios of gamma decay (DLS). The data on nuclear discrete levels are based on the Evaluated

  10. Isospin Character of the Pygmy Dipole Resonance in Sn-124

    NARCIS (Netherlands)

    Endres, J.; Litvinova, E.; Savran, D.; Butler, P. A.; Harakeh, M. N.; Harissopulos, S.; Herzberg, R. -D.; Kruecken, R.; Lagoyannis, A.; Pietralla, N.; Ponomarev, V. Yu; Popescu, L.; Ring, P.; Scheck, M.; Sonnabend, K.; Stoica, V. I.; Wörtche, H. J.; Zilges, A.

    2010-01-01

    The pygmy dipole resonance has been studied in the proton-magic nucleus Sn-124 with the (alpha, alpha'gamma) coincidence method at E-alpha = 136 MeV. The comparison with results of photon-scattering experiments reveals a splitting into two components with different structure: one group of states

  11. Resonant Dipole Nanoantenna Arrays for Enhanced Terahertz Spectroscopy

    KAUST Repository

    Toma, A.

    2015-08-04

    Our recent studies on dipole nanoantenna arrays resonating in the terahertz frequency range (0.1 – 10 THz) will be presented. The main near- and far-field properties of these nanostructures will be shown and their application in enhanced terahertz spectroscopy of tiny quantities of nanomaterials will be discussed.

  12. Actual problems of giant resonance physics

    International Nuclear Information System (INIS)

    Zhalov, M.B.; Sliv, L.A.

    1982-01-01

    The raper deals with the discussion of theoretical problems associated with investigation into nuclear giant multipole resoonances (GMR). Analysis of test data on inelastic scattering of particles on nuclei is carried out to obtain the main GMR characteristics from the present experimental data. Giant isoscalar resonances and their structures in the random phase approximatmion (RPA) with Skyrm forces described by the microscopic theory are discussed. Cross section of 40 Ca excitation in reaction of α-particle inelastic scattering calculated in RPA with exact accountancy of one-nucleon continuum is graphically displayed as an example. Modified RPA used for calculation of GMR width is suggested. Conducted is comparison of energies of 40 Ca, 58 Ni, 90 Zr, 208 Pb nuclei isoscalar resonances calculated in RPA and their contributions to energy weighted sum rule the results of which are tabulated. Integral strength of resonance excitation in RPA by inelastic-scattered α particles and protons on 40 Ca and 208 Pb nuclei is considered. Channels of GMR disintegration are discussed. The most significant theoretical and experimental problems the solution of which is necessary for complete investigation of GMR are pointed out

  13. Monopole Giant Resonances and TDHF boundary conditions

    International Nuclear Information System (INIS)

    Stevenson, P.D.; Almehed, D.; Reinhard, P.-G.; Maruhn, J.A.

    2007-01-01

    Using time-dependent Hartree-Fock, we induce isoscalar and isovector monopole vibrations and follow the subsequent vibrations of both the same and opposite isospin nature in the N Z nucleus 132 Sn. By suitable scaling of the proton and neutron parts of the excitation operators, the coupling between the modes is studied, and the approximate normal modes found. Chaotic dynamics are then analysed in the isoscalar giant monopole resonance by using reflecting boundaries in a large space to build up a large number of 0 + states whose spacings are then analysed. A Wigner-like distribution is found

  14. Isoscalar giant resonances in a relativistic model

    International Nuclear Information System (INIS)

    L'Huillier, M.; Nguyen Van Giai.

    1988-07-01

    Isoscalar giant resonances in finite nuclei are studied in a relativistic Random Phase Approximation (RRPA) approach. The model is self-consistent in the sense that one set of coupling constants generates the Dirac-Hartree single-particle spectrum and the residual particle-hole interaction. The RRPA is used to calculate response functions of multipolarity L = 0,2,3, and 4 in light and medium nuclei. It is found that monopole and quadrupole modes exhibit a collective character. The peak energies are overestimated, but not as much as one might think if the bulk properties (compression modulus, effective mass) were the only relevant quantities

  15. Evidence for deformation effect on the giant monopole resonance

    International Nuclear Information System (INIS)

    Buenerd, M.; Lebrun, D.; Martin, P.; de Saintignon, P.; Perrin, C.

    1980-01-01

    The giant monopole resonance in the region of deformed nuclei has been investigated by inelastic scattering of 108.5 MeV 3 He at very small scattering angles. Evidence is reported for coupling between the giant monopole and giant quadrupole vibrations, based both on energy shift and transition strength

  16. Induced dipole-dipole coupling between two atoms at a migration resonance

    Science.gov (United States)

    Kaur, Maninder; Mian, Mahmood

    2018-05-01

    Results of numerical simulations for the resonant energy exchange phenomenon called Migration reaction between two cold Rydberg atoms are presented. The effect of spatial interatomic distance on the onset of peculiar coherent mechanism is investigated. Observation of Rabi-like population inversion oscillation at the resonance provides a clear signature of dipole induced exchange of electronic excitations between the atoms. Further we present the results for the dependence of expectation value of the interaction hamiltonian on the interatomic distance, which is responsible for energy exchange process. The results of this observation endorse the range of inter atomic distance within which the excitation exchange process occurs completely or partially. Migration process enhance the Rydberg-Rydberg interaction in the absence of an external field, under the condition of the zero permanent dipole moments. Our next observation sheds light on the fundamental mechanism of induced electric fields initiated by the oscillating dipoles in such energy exchange processes. We explore the dependence of induced electric field on the interatomic distance and angle between the dipoles highlighting the inverse power law dependence and anisotropic property of the field. We put forward an idea to utilise the coherent energy exchange process to build efficient and fast energy transfer channels by incorporating more atoms organised at successive distances with decreasing distance gradient.

  17. The sympletic model for giant monopole resonances

    International Nuclear Information System (INIS)

    Oliveira, M.M.B.M.

    1985-01-01

    Following recently published articles, it's investigated how to apply the sympletic model to the study of giant monopole resonances in spherical nuclei. The results obtained agree with those already published for monopole mode energies, wave functions, radii and nuclear incompressibility of 16 O and 40 Ca nuclei. An analyse of how the spurious center-of-mass motion influence resonance energies is made. The sum rules of the monopole operator, m-bar e , o ≤ e ≤ 3, are calculated, demonstrating at first that they are conserved in the sympletic model. Then it's studied, for those sum rules, the importance of n-boson correlations in the fundamental state, which is an extension of those sum rules, of the analysis for the nuclear incompressibility, performed in above mentioned articles. (Author) [pt

  18. Giant resonances in hot rotating nuclei

    International Nuclear Information System (INIS)

    Ring, P.

    1992-01-01

    Present theoretical descriptions of the giant resonances in hot rotating nuclei are reviewed. Mean field theory is used as a basis for the description of the hot compound states. Starting from the static solution at finite temperature and with fixed angular momentum small amplitude collective vibrations are calculated in the frame work of finite temperature random phase approximation for quasi-particles. The effect of pairing at low temperatures as well as the effect of rotations on the position of the resonance maxima are investigated. Microscopic and phenomenological descriptions of the damping mechanisms are reviewed. In particular it turns out that fluctuations play an important role in understanding of the behaviour of the width as a function of the temperature. Motional narrowing is critically discussed. (author). 99 refs., 5 figs

  19. Spin-flip measurements in the proton inelastic scattering on 12C and giant resonance effects

    International Nuclear Information System (INIS)

    De Leo, R.; D'Erasmo, G.; Ferrero, F.; Pantaleo, A.; Pignanelli, M.

    1975-01-01

    Differential cross sections and spin-flip probabilities (SFP) for the inelastic scattering of protons, exciting the 2 + state at 4.43 MeV in 12 C, have been measured at several incident energies between 15.9 and 37.6 MeV. The changes in the shape of the SFP angular distributions are rather limited, while the absolute values show a pronounced increase, resonant like, in two energy regions centered at about 20 and 29 MeV. The second resonance reproduces very closely the energy dependence of the E2 giant quadrupole strength found in a previous experiment. The resonance at 20 MeV should correspond to a substructure of the E1 giant dipole resonance. (Auth.)

  20. Condensed matter view of giant resonance phenomena

    International Nuclear Information System (INIS)

    Zangwill, A.

    1987-01-01

    The intent of this article is to present a view of giant resonance phenomena (an essentially atomic phenomenon) from the perspective of a condensed matter physicist with an interest in the optical properties of matter. As we shall see, this amounts to a particular prejudice about how one should think about many-body effects in a system of interacting electrons. Some of these effects are special to condensed matter systems and will be dealt with in the second half of this paper. However, it turns out that the authors view of the main ingredient to a giant resonance differs significantly from that normally taken by scientists trained in the traditional methods of atomic physics. Therefore, in the first section the author will take advantage of the fact that his contribution to this volume was composed and delivered to the publishers somewhat after the conclusion of the School (rather than before as requested by the organizers) and try to clearly distinguish the differences of opinion presented by the lecturers from the unalterable experimental facts. 46 references, 9 figures

  1. Decay of giant resonance E2 isoscalar in heavy nuclei

    International Nuclear Information System (INIS)

    Herdade, S.B.

    1980-01-01

    In this work, it is made a study of the giant resonance E2 isoscalar, in heavy nuclei. Fission probabilities for this resonance were determined by various authors, in different experiments, for 238 U. (A.C.A.S.) [pt

  2. Semimicroscopic description of the giant quadrupole resonances in deformed nuclei

    International Nuclear Information System (INIS)

    Kurchev, G.; Malov, L.A.; Nesterenko, V.O.; Soloviev, V.G.

    1976-01-01

    The calculation results of the giant quadrupole isoscalar and isovector resonances performed within the random phase approximation are represented. The strength functions for E2-transitions are calculated for doubly even deformed nuclei in the regions 150 (<=) A < 190 and 228 (<=) A < 248 in the energy interval (0-40) MeV. The following integral characteristics of giant quadrupole resonances are obtained: the position, widths, the contribution to the energy weighted sum rule and the contribution to the total cross section of photoabsorption. The calculations have shown that giant quadrupole resonances are common for all the considered nuclei. The calculated characteristics of the isoscalar giant quadrupole resonance agree with the available experimental data. The calculations also show that the semimicroscopic theory can be successfully applied for the description of giant multipole resonances

  3. 750 GeV diphoton resonance and electric dipole moments

    Directory of Open Access Journals (Sweden)

    Kiwoon Choi

    2016-09-01

    Full Text Available We examine the implication of the recently observed 750 GeV diphoton excess for the electric dipole moments of the neutron and electron. If the excess is due to a spin zero resonance which couples to photons and gluons through the loops of massive vector-like fermions, the resulting neutron electric dipole moment can be comparable to the present experimental bound if the CP-violating angle α in the underlying new physics is of O(10−1. An electron EDM comparable to the present bound can be achieved through a mixing between the 750 GeV resonance and the Standard Model Higgs boson, if the mixing angle itself for an approximately pseudoscalar resonance, or the mixing angle times the CP-violating angle α for an approximately scalar resonance, is of O(10−3. For the case that the 750 GeV resonance corresponds to a composite pseudo-Nambu–Goldstone boson formed by a QCD-like hypercolor dynamics confining at ΛHC, the resulting neutron EDM can be estimated with α∼(750 GeV/ΛHC2θHC, where θHC is the hypercolor vacuum angle.

  4. Effects of thermal and particle-number fluctuations on the giant isovector dipole modes for the 58Ni nucleus in the finite-temperature random-phase approximation

    International Nuclear Information System (INIS)

    Nguyen Dinhdang; Nguyen Zuythang

    1988-01-01

    Using the realistic single-particle energy spectrum obtained in the Woods-Saxon nucleon mean-field potential, we calculate the BCS pairing gap for 58 Ni as a function of temperature taking into account the thermal and particle-number fluctuations. The strength distributions of the electric dipole transitions and the centroids of the isovector giant dipole resonance (IV-GDR) are computed in the framework of the finite-temperature random-phase approximation (RPA) based on the Hamiltonian of the quasiparticle-phonon nuclear model with separate dipole forces. It is shown that the change of the pairing gap at finite temperature can noticeably influence the IV-GDR localisation in realistic nuclei. By taking both thermal and quasiparticle fluctuations in the pairing gap into account the effect of the phase transition from superfluid to normal in the temperature dependence of the IV-GDR centroid is completely smeared out. (author)

  5. Spin isovector giant resonances in (n,p) reactions

    International Nuclear Information System (INIS)

    Spicer, B.M.

    1997-01-01

    The present status of the study of spin-flip isovector giant resonances, using the (n,p) charge exchange reaction, is reviewed. After a brief history of the discovery of these giant resonances, a critical appraisal of the interpretation of the data in terms of giant resonances is given, along with some of the theoretical advances that impact on the interpretation of these data. A sampling of the results obtained for typical targets is given, followed by the interpretation of these results. A brief statement is made concerning the way forward in experimental technique for nuclear structure research using charge exchange reactions

  6. Spin dipole and quadrupole resonances in 40Ca

    International Nuclear Information System (INIS)

    Baker, F.T.; Love, W.G.; Bimbot, L.; Fergerson, R.W.; Glashausser, C.; Green, A.; Jones, K.; Nanda, S.

    1989-01-01

    Angular distributions of the double differential cross section d 2 σ/dΩ dE(σ) and the spin-flip probability S nn have been measured for inclusive proton inelastic scattering from 40 Ca at 319 MeV. Excitation energies (ω) up to about 40 MeV have been investigated over the angular range from 3.5 degree to 12 degree in the laboratory (0.3 to 0.9 fm -1 ). Here, multipole decompositions of angular distributions of σS nn for the 40 Ca(rvec p,rvec p ') reaction at 319 MeV have been performed in order to compare ΔS=1 strength observed with sum rules. In contrast to the well-known quenching of Gamow-Teller and M1 resonances, the spin-dipole resonance has a total measured strength which is larger than that predicted by the energy-weighted sum rule. The spin-dipole strength distribution supports asymmetric widths predicted by calculations including 2p-2h mixing. The spin-quadrupole resonance is observed near ω=35 MeV and its total strength for ω<40 MeV estimated

  7. Studies of the giant resonances in heavy nuclei

    International Nuclear Information System (INIS)

    Cataldi, M.I.C.

    1986-01-01

    Experimental measurements of the eletrodisintegration cross section in 181 Ta, 208 Pb and 209 Bi nuclei are made in the Linear Accelerator of the IFUSP-Brazil. The cross section is obtained by the direct counting of the emitted neutrons, in an electron excitation energy range between 8 to 22 MeV. The experimental data are analysed throught the virtual photon method, with the aim of obtaining the isoscalar and isovectorial electric quadrupole giant resonance (E2GR) intensities, as well as the magnetic dipole intensity. For each studied nucleus the results obtained for the E2GR, isoscalar and isovectorial, are compared with the photodisintegration cross section measured by the Saclay and Livermore laboratories. From this comparison, it is observed that the photodisintegration cross sections are compatibles with the existence of an isovector E2GR, located between 120 to 130 A -1/3 Mev and which exhaust around 100% of the Energy-Weighted Sum rules (EWSR). (L.C.) [pt

  8. Excitation of giant resonances via charge exchange reactions

    International Nuclear Information System (INIS)

    Goodman, C.D.

    1979-01-01

    Charge-exchange reactions can be useful for identifying isovector resonances. At present the most promising use of charge-exchange reactions with respect to giant resonances is to locate and study Gamow-Teller (GT) resonances. Detailed comparisons between GT and M1 strengths can yield further structure information. 7 figures

  9. Decay pattern of the Pygmy Dipole Resonance in 130Te

    Science.gov (United States)

    Isaak, J.; Beller, J.; Fiori, E.; Krtička, M.; Löher, B.; Pietralla, N.; Romig, C.; Rusev, G.; Savran, D.; Scheck, M.; Silva, J.; Sonnabend, K.; Tonchev, A.; Tornow, W.; Weller, H.; Zweidinger, M.

    2014-03-01

    The electric dipole strength distribution in 130Te has been investigated using the method of Nuclear Resonance Fluorescence. The experiments were performed at the Darmstadt High Intensity Photon Setup using bremsstrahlung as photon source and at the High Intensity overrightarrow γ -Ray Source, where quasi-monochromatic and polarized photon beams are provided. Average decay properties of 130Te below the neutron separation energy are determined. Comparing the experimental data to the predictions of the statistical model indicate, that nuclear structure effects play an important role even at sufficiently high excitation energies. Preliminary results will be presented.

  10. Investigation of the Pygmy Dipole Resonance in {sup 60}Ni

    Energy Technology Data Exchange (ETDEWEB)

    Fritzsche, Matthias; Pietralla, Norbert; Romig, Christopher; Savran, Deniz; Sonnabend, Kerstin [Institut fuer Kernphysik, Technische Universitaet, Darmstadt (Germany); Rusev, Gencho; Tonchev, Anton P.; Tornow, Werner; Weller, Henry R. [Triangle Universities Nuclear Laboratory, Duke University, Durham, NC (United States); Zilges, Andreas [Institut fuer Kernphysik, Universitaet Koeln (Germany)

    2009-07-01

    At the High Intensity Photon Setup (HIPS) at S-DALINAC in Darmstadt {sup 60}Ni was investigated with unpolarized bremsstrahlung with energies up to 8.0 MeV and 9.9 MeV, respectively. Determination of spin and parity quantum numbers and absolute transition strengths was possible, using HPGe detectors placed under different angles. To assign also parity quantum numbers, the polarized photon beam of the High Intensity Gamma Source (HI{gamma}S) at Duke University was used. With the combined results, evidence of the Pygmy Dipole Resonance in {sup 60}Ni was found.

  11. Decay pattern of the Pygmy Dipole Resonance in 130Te

    Directory of Open Access Journals (Sweden)

    Isaak J.

    2014-03-01

    Full Text Available The electric dipole strength distribution in 130Te has been investigated using the method of Nuclear Resonance Fluorescence. The experiments were performed at the Darmstadt High Intensity Photon Setup using bremsstrahlung as photon source and at the High Intensity γ→$\\overrightarrow \\gamma $-Ray Source, where quasi-monochromatic and polarized photon beams are provided. Average decay properties of 130Te below the neutron separation energy are determined. Comparing the experimental data to the predictions of the statistical model indicate, that nuclear structure effects play an important role even at sufficiently high excitation energies. Preliminary results will be presented.

  12. Dramatic distortion of the 4d giant resonance by the C{sub 60} fullerene shell

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M Ya [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Baltenkov, A S [Arifov Institute of Electronics, Akademgorodok, 700125 Tashkent (Uzbekistan); Chernysheva, L V [A F Ioffe Physical-Technical Institute, St Petersburg 194021 (Russian Federation); Felfli, Z [Department of Physics and Center for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta, GA 30314 (United States); Msezane, A Z [Department of Physics and Center for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta, GA 30314 (United States)

    2005-05-28

    The photoionization cross section for the endohedral Xe at C{sub 60} atom is investigated within the framework of representing the C{sub 60} by a delta-type potential. Results demonstrate that in Xe at C{sub 60}, the 4d giant resonance is distorted significantly when compared with that of the isolated Xe atom. The reflection of the photoelectron waves by the C{sub 60} causes strong oscillations in the photoionization cross section resulting in the replacement of the Xe 4d giant resonance by four prominent peaks. The approximation of C{sub 60} by an infinitely thin real potential preserves reasonably well the sum rule for the 4d electrons but modifies the dipole polarizability of the 4d shell. (letter to the editor)

  13. Nuclear elasticity applied to giant resonances of fast rotating nuclei

    International Nuclear Information System (INIS)

    Jang, S.; Bouyssy, A.

    1987-06-01

    Isoscalar giant resonances in fast rotating nuclei are investigated within the framework of nuclear elasticity by solving the equation of motion of elastic nuclear medium in a rotating frame of reference. Both Coriolis and centrifugal forces are taken into account. The nuclear rotation removes completely the azimuthal degeneracy of the giant resonance energies. Realistic large values of the angular velocity, which are still small as compared to the giant resonance frequencies, are briefly reviewed in relation to allowed high angular momenta. It is shown that for the A=150 region, the Coriolis force is dominating for small values (< ∼ 0.05) of the ratio of angular velocity to resonance frequency, whereas the centrifugal force plays a prominent part in the shift of the split resonance energies for larger values of the ratio. Typical examples of the resonance energies and their fragmentation due to both rotation and deformation are given

  14. Development of the new gamma-ray calorimeter for the measurement of Pigmy Dipole Resonance

    Science.gov (United States)

    Shikata, Mizuki; Nakamura, Takashi; Togano, Yasuhiro; Kondo, Yosuke

    2014-09-01

    A new γ-ray calorimeter CATANA (CAlorimeter for gamma γ-ray Transition in Atomic Nuclei at high isospin Asynmetry) has been developed to measure highly excited states like the pygmy dipole resonance and the giant dipole resonance. CATANA will be used with the SAMURAI spectrometer at RIBF. The excitation energy spectrum will be reconstructed combining the invariant mass of the reaction products measured by SAMURAI and γ-ray energies from CATANA. CATANA has focused on achieving a high detection efficiency. It is calculated as 56% for 1 MeV γ-rays from beam with a velocity of β = 0.6. The CATANA array consists of 200 CsI(Na) crystals and covers angles from 10 to 120 degrees along the beam axis. In this study, we have tested prototype crystals of CATANA to evaluate their performance. A position dependence of the light input have been measured and compared with a Monte-Carlo simulation based on GEANT4. In this talk, we will report the design of CATANA and the result of the tests and the simulation.

  15. Fluid dynamics of giant resonances on high spin states

    International Nuclear Information System (INIS)

    Di Nardo, M.; Di Toro, M.; Giansiracusa, G.; Lombardo, U.; Russo, G.

    1983-01-01

    We describe giant resonances built on high spin states along the yrast line as scaling solutions of a linearized Vlasov equation in a rotating frame obtained from a TDHF theory in phase space. For oblate cranked solutions we get a shift and a splitting of the isoscalar giant resonances in terms of the angular velocity. Results are shown for 40 Ca and 168 Er. The relative CM strengths are also calculated. (orig.)

  16. Giant resonances in free atoms and in clusters

    International Nuclear Information System (INIS)

    Brechignac, C.; Connerade, J.P.

    1994-01-01

    A review of recent developments in the study of giant resonances in free atoms and in clusters is presented, with particular emphasis on the transition from free atoms to atoms in the condensed phase. Giant resonances in alkali and related metallic clusters due to the excitation of closed shells of delocalized electrons are also reviewed and the relation between different types of collective oscillations is discussed. (author)

  17. Direct vs statistical decay of nuclear giant multipole resonances

    International Nuclear Information System (INIS)

    Dias, H.; Hussein, M.S.; Carlson, B.V.; Merchant, A.C.; Adhikari, S.K.

    1986-01-01

    A theoretical framework for the description of the decay of giant multipole resonances id developed. Besides the direct decay, both the pre-equilibrium and statistical (compound) decays are taken into account in a consistent way. It is shown that the statistical decay of the giant resonance is not necessarily described by the Hauser-Feshbach theory owing to the presence of a mixing parameter, which measures the degree of fragmentation. Applications are made to several cases. (Author) [pt

  18. Giant 4p-quadrupole resonances in the Rare Earths

    International Nuclear Information System (INIS)

    Matthew, J.A.D.; Netzer, F.P.; Clark, C.W.; Morar, J.F.

    1987-01-01

    X-ray absorption of Ce obtained by partial secondary yield, is compared with previously obtained electron-energy loss measurements in reflection mode. The absence of a strong feature below 4p 3/2 threshold in photon absorption provides confirmation that the peak in EELS is nondipole in character. Theoretical analysis supports interpretation in terms of a p-f giant quadrupole resonance, a result which broadens the analogy between giant resonances in atomic and nuclear physics

  19. Giant resonances in atoms and in fluorine cage molecules

    International Nuclear Information System (INIS)

    Mansfield, M.W.D.

    1987-01-01

    Giant resonances in the photoabsorption spectra of atoms occur in the extreme ultraviolet region of the electromagnetic spectrum. In order to observe absorption spectra in this region it is necessary to generate columns of atomic vapor which will often by very hot and chemically aggressive, and to contain them without solid windows between two regions of high vacuum, the spectrometer and the light source, usually an electron synchrotron. The technical problems are often formidable so that although it had long been recognized that giant resonances in solid lanthanides were essentially atomic phenomena (Fomichev et al. 1967, Dehmer et al. 1971) earlier investigations of giant resonances in atoms were limited to the more manageable elements which precede the transition rows, the inert gases, alkali and alkaline earth elements. In this paper the authors discusses the spectra of transition row atoms in order of decreasing localization (Smith and Kmetko 1983) viz. 4d → f, 5d → f, 3p → d, 4p → d and 5p → d. He tends to avoid discussion of the giant resonances themselves because their profiles and interpretation will be discussed comprehensively by other contributors. Instead he concentrates on the detailed analyses which have been attempted of the discrete structure which usually accompanies giant resonances in atoms. Interpretation of this structure can provide accurate determinations of thresholds for inner shell excitation in atoms and can also be used to anticipate structure which may overlie the giant resonances and distort their profiles. 75 references, 21 figures

  20. Isoscalar and isovector giant resonances in a self-consistent phonon coupling approach

    Energy Technology Data Exchange (ETDEWEB)

    Lyutorovich, N.; Tselyaev, V. [Physical Faculty, St. Petersburg State University, RU-198504 St. Petersburg (Russian Federation); Speth, J., E-mail: J.Speth@fz-juelich.de [Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich (Germany); Krewald, S.; Grümmer, F. [Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich (Germany); Reinhard, P.-G. [Institut für Theoretische Physik II, Universität Erlangen-Nürnberg, D-91058 Erlangen (Germany)

    2015-10-07

    We present fully self-consistent calculations of isoscalar giant monopole and quadrupole as well as isovector giant dipole resonances in heavy and light nuclei. The description is based on Skyrme energy-density functionals determining the static Hartree–Fock ground state and the excitation spectra within random-phase approximation (RPA) and RPA extended by including the quasiparticle-phonon coupling at the level of the time-blocking approximation (TBA). All matrix elements were derived consistently from the given energy-density functional and calculated without any approximation. As a new feature in these calculations, the single-particle continuum was included thus avoiding the artificial discretization usually implied in RPA and TBA. The step to include phonon coupling in TBA leads to small, but systematic, down shifts of the centroid energies of the giant resonances. These shifts are similar in size for all Skyrme parametrizations investigated here. After all, we demonstrate that one can find Skyrme parametrizations which deliver a good simultaneous reproduction of all three giant resonances within TBA.

  1. Isoscalar and isovector giant resonances in a self-consistent phonon coupling approach

    Directory of Open Access Journals (Sweden)

    N. Lyutorovich

    2015-10-01

    Full Text Available We present fully self-consistent calculations of isoscalar giant monopole and quadrupole as well as isovector giant dipole resonances in heavy and light nuclei. The description is based on Skyrme energy-density functionals determining the static Hartree–Fock ground state and the excitation spectra within random-phase approximation (RPA and RPA extended by including the quasiparticle-phonon coupling at the level of the time-blocking approximation (TBA. All matrix elements were derived consistently from the given energy-density functional and calculated without any approximation. As a new feature in these calculations, the single-particle continuum was included thus avoiding the artificial discretization usually implied in RPA and TBA. The step to include phonon coupling in TBA leads to small, but systematic, down shifts of the centroid energies of the giant resonances. These shifts are similar in size for all Skyrme parametrizations investigated here. After all, we demonstrate that one can find Skyrme parametrizations which deliver a good simultaneous reproduction of all three giant resonances within TBA.

  2. Excitation and photon decay of giant multipole resonances

    International Nuclear Information System (INIS)

    Bertrand, F.E.; Beene, J.R.

    1990-01-01

    A brief review of the excitation of giant multipole resonances via Coulomb excitation is given which emphasizes the very large cross sections that can be realized through this reaction for both isoscalar and isovector resonances. Discussion and results where available, are provide for the measurement of the photon decay of one and two phonon giant resonances. It is pointed out throughout the presentation that the use of E1 photons as a ''tag'' provides a means to observe weakly excited resonances that cannot be observed in the singles spectra. 14 refs., 12 figs., 1 tab

  3. Modification of the Xe 4d giant resonance by the C60 shell in molecular Xe at C60

    International Nuclear Information System (INIS)

    Amusia, M. Ya.; Baltenkov, A. S.; Chernysheva, L. V.; Felfli, Z.; Msezane, A. Z.

    2006-01-01

    It is demonstrated that in photoabsorption of the 4d 10 subshell of a Xe atom in molecular Xe at C 60 , the 4d giant resonance that characterizes the isolated Xe atom is distorted significantly. The reflection of photoelectron waves by the C 60 shell leads to profound oscillations in the photoionization cross section such that the Xe giant resonance is transformed into four strong peaks. Similarly, the angular anisotropy parameters, both dipole and nondipole, are also modified. The method of calculation is based on the approximation of the C 60 shell by an infinitely thin bubble potential that leaves the sum rule for the 4d-electrons almost unaffected, but noticeably modifies the dipole polarizability of the 4d-shell

  4. Magnetosonic resonance in a dipole-like magnetosphere

    Directory of Open Access Journals (Sweden)

    A. S. Leonovich

    2006-09-01

    Full Text Available A theory of resonant conversion of fast magnetosonic (FMS waves into slow magnetosonic (SMS oscillations in a magnetosphere with dipole-like magnetic field has been constructed. Monochromatic FMS waves are shown to drive standing (along magnetic field lines SMS oscillations, narrowly localized across magnetic shells. The longitudinal and transverse structures, as well as spectrum of resonant SMS waves are determined. Frequencies of fundamental harmonics of standing SMS waves lie in the range of 0.1–1 mHz, and are about two orders of magnitude lower than frequencies of similar Alfvén field line resonance harmonics. This difference makes an effective interaction between these MHD modes impossible. The amplitude of SMS oscillations rapidly decreases along the field lines from the magnetospheric equator towards the ionosphere. In this context, magnetospheric SMS oscillations cannot be observed on the ground, and the ionosphere does not play any role either in their generation or dissipation. The theory developed can be used to interpret the occurrence of compressional Pc5 waves in a quiet magnetosphere with a weak ring current.

  5. The Giant Dipole Resonance in hot nuclei. Experimental aspects

    International Nuclear Information System (INIS)

    Alamanos, N.; Auger, F.

    1994-12-01

    Some of the most recent experimental results on the GDR in hot nuclei are presented. All data on the γ-decay of the GDR show a saturation of the apparent width and a saturation of the yield. However, it is not clear until now, if these effects are related to a GDR width which either saturates or increases continuously with the excitation energy. Very new data associated to selected exit channels could help to clarify the situation. (author). 14 refs., 7 figs

  6. Evolution of giant dipole resonance width at low temperatures ...

    Indian Academy of Sciences (India)

    techniques. Several experiments have been performed by bombarding 7–12 MeV/nucleon alpha beam on various targets (63Cu, 115In and 197Au) and new datasets ... appears to be constant at its ground state value until a critical temperature is reached and subse- ..... it was 38.6 MeV for 63Cu at 35 MeV incident energy.

  7. Giant magnons and spiky strings in the Schrödinger/dipole-deformed CFT correspondence

    Science.gov (United States)

    Georgiou, George; Zoakos, Dimitrios

    2018-02-01

    We construct semi-classical string solutions of the Schrödinger Sch 5 × S 5 spacetime, which is conjectured to be the gravity dual of a non-local dipole-deformed CFT. They are the counterparts of the giant magnon and spiky string solutions of the undeformed AdS 5 × S 5 to which they flow when the deformation parameter is turned off. They live in an S 3 subspace of the five-sphere along the directions of which the B-field has non-zero components, having also extent in the Sch 5 part of the metric. Finally, we speculate on the form of the dual field theory operators.

  8. Multipole resonance in the interaction of a spherical Ag nanoparticle with an emitting dipole

    International Nuclear Information System (INIS)

    Liu Jia-Dong; Song Feng; Zhang Jun; Wang Feng-Xiao; Wang Li-Chao; Liu Shu-Jing

    2014-01-01

    The effect of multipole resonance in the interaction between a spherical metallic nanoparticle (MNP) and an emitting dipole is studied with the Mie theory. The results show that the absorption peak of the MNP with respect to the field of the emitting dipole is blue-shifted with the decrease of the spacing between MNP and emitting dipole due to the enhanced multipole resonance. At a short distance, the enhanced multipole terms of scattering are not obvious compared with the dipole term. For the decay rate of the emitting dipole, multipole resonance brings about the enhancement of it largely at short spacing. For the radiative decay rate, the behavior is quite different. The dipole term is dominant at a short spacing, and the multipole term is dominant at a larger spacing. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  9. The direct neutron decay of giant resonances in 208Pb

    International Nuclear Information System (INIS)

    Bracco, A.

    1988-01-01

    The neutron decay of the giant multipole resonance region from 9 to 15 MeV of excitation energy in 208 Pb has been studied. Neutron branching ratios for the decay to the ground state and to the low-lying excited states of 207 Pb were measured as a function of the excitation energy of 208 Pb and compared to Hauser-Feshbach calculations. While the neutron branching ratios from the energy region of the isoscalar giant quadrupole resonance are reproduced by the calculations, the ratios from the energy region of the isoscalar giant monopole resonance show a conspicuous excess with respect to the statistical model predictions. The neutron yield from this energy region was analysed in terms of a multistep model of the compound nucleus which includes collective doorway channels. The total direct escape width as well as the associated direct partial escape widths to the lowest five valence hole states of 207 Pb were determined. (orig.)

  10. Giant monopole resonance in transitional and deformed nuclei

    International Nuclear Information System (INIS)

    Garg, U.; Bogucki, P.; Bronson, J.D.; Lui, Y.; Youngblood, D.H.

    1984-01-01

    Small-angle inelastic α-scattering measurements have been made at E/sub α/ = 129 MeV on /sup 144,148/Sm and /sup 142,146,150/Nd to investigate the giant monopole resonance in transitional and deformed nuclei. The experimental data reveal a mixing of L = 0 and L = 2 modes in 148 Sm resulting in almost identical angular distributions for the two components of the giant resonance peaks in the angular range 2 0 --6 0 . A ''splitting'' of the giant monopole resonance is observed in 150 Nd; the extent of this splitting is smaller than that reported for 154 Sm. Comparison is made with the predictions of various theoretical models

  11. Hybrid model for the decay of nuclear giant resonances

    International Nuclear Information System (INIS)

    Hussein, M.S.

    1986-12-01

    The decay properties of nuclear giant multipole resonances are discussed within a hybrid model that incorporates, in a unitary consistent way, both the coherent and statistical features. It is suggested that the 'direct' decay of the GR is described with continuum first RPA and the statistical decay calculated with a modified Hauser-Feshbach model. Application is made to the decay of the giant monopole resonance in 208 Pb. Suggestions are made concerning the calculation of the mixing parameter using the statistical properties of the shell model eigenstates at high excitation energies. (Author) [pt

  12. Quantum calculation of dipole excitation in fusion reaction

    International Nuclear Information System (INIS)

    Simenel, C.; Chomaz, Ph.; De France, G.

    2000-01-01

    The excitation of the giant dipole resonance by fusion is studied with N/Z asymmetry in the entrance channel. The TDHF solution exhibits a strong dipole vibration which can be associated with a giant vibration along the main axis of a fluctuating prolate shape. The consequences on the gamma-ray emission from hot compound nuclei are discussed. (author)

  13. A Boltzmann equation approach to the damping of giant resonances in nuclei

    International Nuclear Information System (INIS)

    Schuck, P.; Winter, J.

    1983-01-01

    The Vlasov equation plus collision term (Boltzmann equation) represents an appropriate frame for the treatment of giant resonances (zero sound modes) in nuclei. With no adjustable parameters we obtain correct positions and widths for the giant quadrupole resonances. (author)

  14. Surface and temperature effects in isovector giant resonances

    International Nuclear Information System (INIS)

    Lipparini, E.; Stringari, S.

    1988-01-01

    Using the liquid droplet model (LDM) we investigate three different sum rules for the isovector dipole and monopole excitations. Analytical formulae are derived for the excitation energies of these resonances and the predictions are compared with experiments. The role of the surface and the effects of temperature are explicitly discussed. (orig.)

  15. On field line resonances of hydromagnetic Alfven waves in dipole magnetic field

    International Nuclear Information System (INIS)

    Chen, Liu; Cowley, S.C.

    1989-07-01

    Using the dipole magnetic field model, we have developed the theory of field line resonances of hydromagnetic Alfven waves in general magnetic field geometries. In this model, the Alfven speed thus varies both perpendicular and parallel to the magnetic field. Specifically, it is found that field line resonances do persist in the dipole model. The corresponding singular solutions near the resonant field lines as well as the natural definition of standing shear Alfven eigenfunctions have also been systematically derived. 11 refs

  16. A self-consistent semiclassical sum rule approach to the average properties of giant resonances

    International Nuclear Information System (INIS)

    Li Guoqiang; Xu Gongou

    1990-01-01

    The average energies of isovector giant resonances and the widths of isoscalar giant resonances are evaluated with the help of a self-consistent semiclassical Sum rule approach. The comparison of the present results with the experimental ones justifies the self-consistent semiclassical sum rule approach to the average properties of giant resonances

  17. Investigation of the Pygmy Dipole Resonance in (alpha, alpha 'gamma) coincidence experiments

    NARCIS (Netherlands)

    Savran, D.; Babilon, M.; van den Berg, A. M.; Harakeh, M. N.; Hasper, J.; Wortche, H. J.; Zilges, A.

    2007-01-01

    We report on first results from experiments using the (alpha, alpha'gamma) reaction at E alpha = 136 MeV to investigate bound electric dipole (El) excitations building the so-called Pygmy Dipole Resonance (PDR) in the semi-magic nucleus Ce-140. The method of (alpha, alpha'gamma) allows the

  18. Introduction to magnetic resonance and its application to dipole magnet testing

    International Nuclear Information System (INIS)

    Clark, W.G.

    1992-01-01

    An introduction to the features of magnetic resonance that are essential for understanding its application to testing accelerator dipole magnets is presented, including the accuracy that can be expected in field measurements and the factors that limit it. The use of an array of coils to measure the multipole moments of dipole magnets is discussed

  19. Vacuum fluctuations and radiation reaction contributions to the resonance dipole-dipole interaction between two atoms near a reflecting boundary

    Science.gov (United States)

    Zhou, Wenting; Rizzuto, Lucia; Passante, Roberto

    2018-04-01

    We investigate the resonance dipole-dipole interaction energy between two identical atoms, one in the ground state and the other in the excited state, interacting with the electromagnetic field in the presence of a perfectly reflecting plane boundary. The atoms are prepared in a correlated (symmetric or antisymmetric) Bell-type state. Following a procedure due to Dalibard et al. [J. Dalibard et al., J. Phys. (Paris) 43, 1617 (1982);, 10.1051/jphys:0198200430110161700 J. Phys. (Paris) 45, 637 (1984), 10.1051/jphys:01984004504063700], we separate the contributions of vacuum fluctuations and radiation reaction (source) field to the resonance interaction energy between the two atoms and show that only the source field contributes to the interatomic interaction, while vacuum field fluctuations do not. By considering specific geometric configurations of the two-atom system with respect to the mirror and specific choices of dipole orientations, we show that the presence of the mirror significantly affects the resonance interaction energy and that different features appear with respect to the case of atoms in free space, for example, a change in the spatial dependence of the interaction. Our findings also suggest that the presence of a boundary can be exploited to tailor and control the resonance interaction between two atoms, as well as the related energy transfer process. The possibility of observing these phenomena is also discussed.

  20. Isovector giant monopole resonances: A sum-rule approach

    International Nuclear Information System (INIS)

    Goeke, K.; Bonn Univ.; Castel, B.

    1980-01-01

    Several useful sum rules associated with isovector giant monopole resonances are calculated for doubly closed shell nuclei. The calculation is based on techniques known from constrained and adiabatic time-dependent Hartree-Fock theories and assume various Skyrme interactions. The results obtained form, together with the compiled literature, the basis for a quantitative description of the RPA strength distribution in terms of energy-weighted moments. These, together with strength distribution properties, are determined by a hierarchy of determinantal relations between moments. The isovector giant monopole resonance turns out to be a rather broad resonance centered at E = 46 Asup(-1/10) MeV with an extended width of more than 16 MeV. The consequences regarding isospin impurities in the nuclear ground state are discussed. (orig.)

  1. Collisional width of giant resonances and interplay with Landau damping

    International Nuclear Information System (INIS)

    Bonasera, A.; Burgio, G.F.; Di Toro, M.; Wolter, H.H.

    1989-01-01

    We present a semiclassical method to calculate the widths of giant resonances. We solve a mean-field kinetic equation (Vlasov equation) with collision terms treated within the relaxation time approximation to construct a damped strength distribution for collective motions. The relaxation time is evaluated from the time evolution of distortions in the nucleon momentum distribution using a test-particle approach. The importance of an energy dependent nucleon-nucleon cross section is stressed. Results are shown for isoscalar giant quadrupole and octupole motions. A quite important interplay between self-consistent (Landau) and collisional damping is revealed

  2. Magnetic dipole strength in 128Xe and 134Xe in the spin-flip resonance region

    Science.gov (United States)

    Massarczyk, R.; Rusev, G.; Schwengner, R.; Dönau, F.; Bhatia, C.; Gooden, M. Â. E.; Kelley, J. Â. H.; Tonchev, A. Â. P.; Tornow, W.

    2014-11-01

    The magnetic dipole strength in the energy region of the spin-flip resonance is investigated in 128Xe and 134Xe using quasimonoenergetic and linearly polarized γ -ray beams at the High-Intensity γ -Ray Source facility in Durham, North Carolina, USA. Absorption cross sections were deduced for the magnetic and electric and dipole strength distributions separately for various intervals of excitation energy, including the strength of states in the unresolved quasicontinuum. The magnetic dipole strength distributions show structures resembling a resonance in the spin-flip region around an excitation energy of 8 MeV. The electric dipole strength distributions obtained from the present experiments are in agreement with the ones deduced from an earlier experiment using broad-band bremsstrahlung instead of a quasimonoenergetic beam. The experimental magnetic and electric dipole strength distributions are compared with phenomenological approximations and with predictions of a quasiparticle random phase approximation in a deformed basis.

  3. Excitation of giant resonances through inelastic scattering of 170 at 84 MeV/u. Fission decay of giant resonances

    International Nuclear Information System (INIS)

    Cabot, C.; Barrette, J.; Mark, S.K.; Turcotte, R.; Xing, J.; Van der Woude, A.; Van Den Berg, A. M.

    1991-01-01

    Inelastic scattering of 84 MeV/u 17 0 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

  4. Study of giant multipole resonances in 40Ca

    International Nuclear Information System (INIS)

    Rost, H.

    1979-01-01

    In the present thesis giant resonance states in 40 Ca were studied by scattering of 104 MeV a particles on 40 Ca and by the reactions 39 K(p vector,p') 39 K and 39 K(p,α) 36 Ar. The scattered α-particles were measured at extreme forward angles (THETAsub(L) = 4 0 -16 0 C), because at forward angles the cross sections for the excitation of states with spin 0 and 1 strongly differ from those with higher spin. The aim of this experiment was first of all the study of the giant resonance region in 40 Ca on the contribution to 0 + or 1 - states. Beside the known electric giant quadrupole resonances at Esub(x) approx. equal to 18.5 MeV (25% EWSR) contributions of EO-strength at Esub(x) approx. equal to 21 MeV (6% EWSR) and indications to a (isoscalar) E1-strength at Esub(x) approx. equal to 14 MeV and Esub(x) approx. equal to 16 MeV were found. At the reactions 39 K(p vector,p') 39 K and 39 K(p,α) 36 Ar in the channels (p,p 0 ),(p,p 4 ), (p,αsub(o)), and (p,α 1 ) at incident energies at about 10 MeV (Esub(x)( 40 Ca) approx. equal to 18 MeV) resonant structures were observed. A scattering phase analysis performed for the elastic proton scattering didn't however yield quantitative results about the resonance parameter. An expansion of the cross sections by Legendre polynomials for the remaining reaction channel didn't allow a conclusion about the dominance of a certain L-value. The only indication to the connection of the observed resonant structures with the giant quadrupole resonance in 40 Ca is therefore the energetic position at about Esub(x) approx. equal to 18 MeV. Altogether the observed structures however were not very pronounced, so it can be concluded, that the excitation of the giant quadrupole resonance in 40 Ca by protons via the ground state of 39 K occurs not very strongly. (orig./HSI) [de

  5. Demonstration of Magnetic Dipole Resonances of Dielectric Nanospheres in the Visible Region

    DEFF Research Database (Denmark)

    Evlyukhin, A. B.; Novikov, S. M.; Zywietz, U.

    2012-01-01

    Strong resonant light scattering by individual spherical Si nanoparticles is experimentally demonstrated, revealing pronounced resonances associated with the excitation of magnetic and electric modes in these nanoparticles. It is shown that the low-frequency resonance corresponds to the magnetic...... dipole excitation. Due to high permittivity, the magnetic dipole resonance is observed in the visible spectral range for Si nanoparticles with diameters of similar to 200 nm, thereby opening a way to the realization of isotropic optical metamaterials with strong magnetic responses in the visible region....

  6. Quantitatively analyzing the mechanism of giant circular dichroism in extrinsic plasmonic chiral nanostructures by tracking the interplay of electric and magnetic dipoles.

    Science.gov (United States)

    Hu, Li; Tian, Xiaorui; Huang, Yingzhou; Fang, Liang; Fang, Yurui

    2016-02-14

    Plasmonic chirality has drawn much attention because of tunable circular dichroism (CD) and the enhancement for chiral molecule signals. Although various mechanisms have been proposed to explain the plasmonic CD, a quantitative explanation like the ab initio mechanism for chiral molecules, is still unavailable. In this study, a mechanism similar to the mechanisms associated with chiral molecules was analyzed. The giant extrinsic circular dichroism of a plasmonic splitting rectangle ring was quantitatively investigated from a theoretical standpoint. The interplay of the electric and magnetic modes of the meta-structure is proposed to explain the giant CD. We analyzed the interplay using both an analytical coupled electric-magnetic dipole model and a finite element method model. The surface charge distributions showed that the circular current yielded by the splitting rectangle ring causes the ring to behave like a magneton at some resonant modes, which then interact with the electric modes, resulting in a mixing of the two types of modes. The strong interplay of the two mode types is primarily responsible for the giant CD. The analysis of the chiral near-field of the structure shows potential applications for chiral molecule sensing.

  7. Observation of the M1 giant resonance by resonance averaging in 106Pd

    International Nuclear Information System (INIS)

    Kopecky, J.

    1987-01-01

    An investigation of capture of 2 keV and 24 keV neutrons in a 105 Pd target resulted in resonance-averaged intensities of primary gamma rays with energies between 5.2 and 9.5 MeV. From these intensities the gamma ray strength functions have been evaluated for E1, M1 and E2 radiation and compared with predictions of the giant resonance theory. The inclusion of an energy dependent spreading width for the E1 giant resonance is necessary. The energy distribution of M1 reduced strength is consistent with an interpretation of a broad resonance around 8.8 MeV. E2 data agrees satisfactorily with the giant extrapolation. (orig.)

  8. Statistical decay of giant monopole resonance in 208Pb

    International Nuclear Information System (INIS)

    Dias, H.; Wolynec, E.

    1984-01-01

    The neutron spectrum from the decay of the monopole giant resonance in 208 Pb is calculated using the known energy levels of 207 Pb. The particle vibrator model is used to assign spins parities to the measured 207 Pb levels, where these were not avaliable from experiments. The results of the Hauser-Feshbach calculation is in excellent agreement with the experimental spectrum, showing that the observed fast neutrons can be completely explained assuming a statistical decay. (Author) [pt

  9. Quantized TDHF for isoscalar giant quadrupole resonances in spherical nuclei

    International Nuclear Information System (INIS)

    Drozdz, S.; Okolowicz, J.; Ploszajczak, M.; Caurier, E.

    1988-01-01

    The time-dependent Hartree-Fock theory supplemented with the regularity and single-valuedness quantization condition for the gauge invariant component of the wavefunction is applied to the description of the centroid energy and escape width of isoscalar giant quadrupole resonances in 16 O, 40 Ca and 110 Zr. Calculations are performed using the Skyrme SIII effective interaction. An important role of the finite oscillation amplitude in the mean-field dynamics is emphasized. (orig.)

  10. Direct vs statistical decay of nuclear giant multipole resonances

    International Nuclear Information System (INIS)

    Hussein, M.S.

    1986-07-01

    A theoretical framework for the description of the decay of giant multipole resonances is developed. Besides the direct decay, both the pre-equilibrium and statistical (compound) decays are taken into account in a consistent way. It is shown that the statistical decay of the GR is not necessarily correctly described by the Hauser-Feshbach theory owing to the presence of a mixing parameter, which measures the degree of fragmentation. Applications are made to several cases. (Author) [pt

  11. Statistical decay of the E1 giant resonance

    International Nuclear Information System (INIS)

    Teruya, N.; Dias, H.; Wolynec, E.

    1987-10-01

    Available esperimental data on neutron decay spectra from the E1 giant resonances in 208 Pb and 209 Bi are compared with the predicted spectra for statistical decay. The calculations are performed using the Hauser-Feshbach formalism with the experimental levels of the residual nuclei. The particle-vibrator model is used to assign spins and parities to experimental levels when those are unknown and also to predict the levels where there is not enough experimental information. (author) [pt

  12. Giant right atrial myxoma: characterization with cardiac magnetic resonance imaging.

    LENUS (Irish Health Repository)

    Ridge, Carole A

    2012-02-01

    A 53-year-old woman presented to the emergency department with a 2-week history of dyspnoea and chest pain. Computed tomography pulmonary angiography was performed to exclude acute pulmonary embolism (PE). This demonstrated a large right atrial mass and no evidence of PE. Transthoracic echocardiography followed by cardiac magnetic resonance imaging confirmed a mobile right atrial mass. Surgical resection was then performed confirming a giant right atrial myxoma. We describe the typical clinical, radiologic, and pathologic features of right atrial myxoma.

  13. Optimization experiments on the study of giant resonance in nuclei

    International Nuclear Information System (INIS)

    Lyubarskij, G.Ya.; Savitskij, G.A.; Fartushnyj, V.A.; Khazhmuradov, M.A.; Levandovskij, S.P.

    1988-01-01

    Optimum choice of the target exposure to a beam in experiments on the study of giant resonances in nuclei is considered. Optimization is aimed at reducing mean square errors of defined formfactors. Four different optimization quality criteria - variances of four form factor experimental values are considered. Variances resulting form optimization are 1.5-2 times as less as variances in real experiment. The effect of experiment design optimization criterion on form factors determination errors is ascertained. 1 ref.; 3 tabs

  14. Theoretical Predictions of Giant Resonances in 94Mo

    Science.gov (United States)

    Golden, Matthew; Bonasera, Giacomo; Shlomo, Shalom

    2016-09-01

    We perform Hartree-Fock based Random Phase Approximation using thirty-three common Skyrme interactions found in the literature for 94Mo. We calculate the strength functions and the Centroid Energies of the Isoscalar Giant Resonances for all multipolarities L0, L1, L2, L3. We compare the calculated Centroid Energies with the experimental value; we also study the Centroid Energy and any correlation it may have with the Nuclear Matter properties of each interaction.

  15. Nuclear Resonance Fluorescence off 54Cr: The Onset of the Pygmy Dipole Resonance

    Science.gov (United States)

    Ries, P. C.; Beck, T.; Beller, J.; Krishichayan; Gayer, U.; Isaak, J.; Löher, B.; Mertes, L.; Pai, H.; Pietralla, N.; Romig, C.; Savran, D.; Schilling, M.; Tornow, W.; Werner, V.; Zweidinger, M.

    2016-06-01

    Low-lying electric and magnetic dipole excitations (E1 and M1) below the neutron separation threshold, particularly the Pygmy Dipole Resonance (PDR), have drawn considerable attention in the last years. So far, mostly moderately heavy nuclei in the mass regions around A = 90 and A = 140 were examined with respect to the PDR. In the present work, the systematics of the PDR have been extended by measuring excitation strengths and parity quantum numbers of J = 1 states in lighter nuclei near A = 50 in order to gather information on the onset of the PDR. The nuclei 50,52,54Cr and 48,50Ti were examined via bremsstrahlung produced at the DArmstadt Superconducting electron Linear Accelerator (S-DALINAC) with photon energies up to 9.7 MeV with the method of nuclear resonance fluorescence. Numerous excited states were observed, many of which for the first time. The parity quantum numbers of these states have been determined at the High Intensity Gamma-ray Source (HIγS) of the Triangle Universities Nuclear Laboratory in Durham, NC, USA. Informations to the methods and the experimental setups will be provided and the results on 54Cr achieved will be discussed with respect to the onset of the PDR.

  16. Random phase approximation: from Giant to Intra-doublet resonances

    International Nuclear Information System (INIS)

    Amusia, M.Ya.

    2004-01-01

    We discuss here the history and current achievements of one of the most powerful approaches of 20th century physics--the random phase approximation (RPA) that permits us to study collective or multiparticle effects in atoms, nuclei, molecules and clusters, as well as in quantum liquids. We concentrate on RPA application to studies of isolated atoms where it permits one to disclose the collective multielectron nature of so-called Giant resonances and predict a number of others, like Interference and Intra-doublet resonances. We present general theory as well as results of concrete calculations for a number of atoms

  17. Random phase approximation: from Giant to Intra-doublet resonances

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M.Ya. E-mail: amusia@vms.huji.ac.il

    2004-06-01

    We discuss here the history and current achievements of one of the most powerful approaches of 20th century physics--the random phase approximation (RPA) that permits us to study collective or multiparticle effects in atoms, nuclei, molecules and clusters, as well as in quantum liquids. We concentrate on RPA application to studies of isolated atoms where it permits one to disclose the collective multielectron nature of so-called Giant resonances and predict a number of others, like Interference and Intra-doublet resonances. We present general theory as well as results of concrete calculations for a number of atoms.

  18. Soft spin-dipole resonances in 40Ca

    International Nuclear Information System (INIS)

    Stuhl, L; Krasznahorkay, A; Csatlós, M; Gulyás, J; Marketin, T; Litvinova, E; Adachi, T; Fujita, H; Hatanaka, K; Hirota, K; Ong, H J; Ishikawa, D; Matsubara, H; Algora, A; Estevez, E; Molina, F; Daeven, J; Guess, C; Meharchand, R; Fujita, Y

    2012-01-01

    High resolution experimental data has been obtained for the 40,42,44,48 Ca( 3 He,t)Sc charge exchange reaction at 420 MeV beam energy, which favors the spin-isospin excitations. The measured angular distributions were analyzed for each state separately, and the relative spin dipole strength has been extracted for the first time. The low-lying spin-dipole strength distribution in 40 Sc shows some interesting periodic gross feature. It resembles to a soft, damped multi-phonon vibrational band with hω= 1.8 MeV, which might be associated to pairing vibrations around 40 Ca.

  19. Magnetic resonance imaging of large and giant intracranial aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, Kenichi; Saito, Akira; Nakasu, Yoko; Matsuda, Masayuki; Handa, Jyoji [Shiga University of Medical Science, Shiga (Japan); Todo, Giro

    1990-06-01

    Twelve large or giant intracranial aneurysms were studied with magnetic resonance (MR) imaging, and the findings were compared with those from computed tomographic (CT) scanning. Characteristic MR features of such aneurysms are: round, extra-axial mass with hypointensity rim; signal void, paradoxical enhancement, or even-echo rephasing due to blood flow; and laminated, eccentric thrombus with increased signal intensity when fresh, perianeurysmal hemorrhage occurs in the acute or subacute stage after aneurysmal rupture. MR imaging, however, often fails to identify or characterize the area of calcification. For the diagnosis of large or giant intracranial aneurysms, MR imaging is apparently superior to CT scanning in differentiating aneurysms from tumors, delineating the blood flow and intraluminal thrombus, and detecting the exact size of the aneurysm. It may also provide useful information concerning the growth mechanisms of aneurysms with or without thrombus formation. (author).

  20. Giant resonance of electrical multipole from droplet model

    International Nuclear Information System (INIS)

    Tauhata, L.

    1984-01-01

    The formalism of the electrical multipole resonance developed from the Droplet nuclear model is presented. It combines the approaches of Goldhaber-Teller (GT) and Steinwedel-Jensen (SJ) and it shows the relative contribution of Coulomb, superficial and neutron excess energies. It also discusses the calculation of half-width. The model evaluates correctly the resonance energies as a function of nuclear mass and allows, through the Mixture Index, the prediction of the complementary participation of modes SJ and GT in the giant nuclear resonance. Values of the mixture index, for each multipolarity, reproduce well the form factors obtained from experiments of charged particle inelastic scattering. The formalism presented for the calculation of the half-width gives a macroscopic description of the friction mechanism. The establishment of the macroscopic structure of the Dissipation Function is used as a reference in the comparison of microscopic calculations. (Author) [pt

  1. Form factors and radiation widths of the giant multipole resonances

    International Nuclear Information System (INIS)

    Denisov, V.Yu.

    1990-01-01

    Simple analytic relations for the form factors of inelastic electron scattering in the Born approximation and radiation widths of the isovector and isoscalar giant multipole resonances are derived. The dynamic relationship between the volume and surface density vibrations were taken into account in this calculation. The form factors in the Born approximation were found to be in satisfactory agreement with experimental data in the region of small transferred momenta. The radiation widths of isoscalar multipole resonances increase when the number of nucleons increase as A 1/3 , and for isovector resonances this dependence has the form f(A)A 1/3 , where f(A) is a slowly increasing function of A. Radiation widths well fit the experimental data

  2. Distribution of radiative strength with excitation energy: the E1 and M1 giant resonances

    International Nuclear Information System (INIS)

    Brown, G.E.; Speth, J.

    1979-01-01

    Calculations of the giant dipole resonance in the particle-hole model, employing empirical values for the unperturbed particle and hole energies, have been unsuccessful in pushing the dipole state to a sufficiently high energy. it is argued that unperturbed levels correspondign to an effective mass of m*/m approx. 0.6 to 0.7 should be employed. The couplings of particles and holes to vibrations are the crucial ingredients in these considerations. More generally, it is argued that the effective mass relevant to excitations near the Fermi surface is that corresponding to empirical single-particle levels, m*/m greater than or equal to 1.0. For particle-hole excitations above the Fermi surface, it is a decreasing function of excitation energy, reaching the above values 0.6 to 0.7 for E greater than or equal to 2 dirac constant/b omega, dirac constant/sub omega/ being the shell spacing. This has the consequence of spreading out the M1 strength. A new interpretation of experimental strengths is proposed

  3. Measurement of isovector giant quadrupole resonance in 40Ca

    International Nuclear Information System (INIS)

    Sims, D.A.; Thompson, M.N.; Rassool, R.; Adler, J.O.; Andersson, B.E.; Hansen, K.; Issaksson, L.; Nilsson, B.; Ruijter, H.; Schroeder, B.; Annand, J.R.M.; McGeorge, J.C.; Crawford, G.I.; Miller, G.J.

    1997-01-01

    The 40 Ca(γ,n) reaction was measured using tagged photons in the energy range 25-50 MeV. Neutrons were detected using two 9-element, liquid scintillator, neutron detectors placed at angles of 55 deg and 125 deg at flight path of 3.2 m. The absolute cross section was determined relative to that for D (γ,n)p, which was measured using a heavy water target. The forward/backward asymmetry in the 40 Ca (γ, n) cross section, resulting from E1/E2 interference has been used to locate and parametrize the isovector giant quadrupole resonance (IVQR). 6 refs., 2 figs

  4. A density variational approach to nuclear giant resonances at zero and finite temperature

    International Nuclear Information System (INIS)

    Gleissl, P.; Brack, M.; Quentin, P.; Meyer, J.

    1989-02-01

    We present a density functional approach to the description of nuclear giant resonances (GR), using Skyrme type effective interactions. We exploit hereby the theorems of Thouless and others, relating RPA sum rules to static (constrained) Hartree-Fock expectation values. The latter are calculated both microscopically and, where shell effects are small enough to allow it, semiclassically by a density variational method employing the gradient-expanded density functionals of the extended Thomas-Fermi model. We obtain an excellent overall description of both systematics and detailed isotopic dependence of GR energies, in particular with the Skyrme force SkM. For the breathing modes (isoscalar and isovector giant monopole modes), and to some extent also for the isovector dipole mode, the A-dependence of the experimental peak energies is better described by coupling two different modes (corresponding to two different excitation operators) of the same spin and parity and evaluating the eigenmodes of the coupled system. Our calculations are also extended to highly excited nuclei (without angular momentum) and the temperature dependence of the various GR energies is discussed

  5. Decay pattern of the Pygmy Dipole Resonance in 140Ce

    Science.gov (United States)

    Isaak, J.; Löher, B.; Savran, D.; Aumann, T.; Beller, J.; Cooper, N.; Derya, V.; Duchêne, M.; Endres, J.; Fiori, E.; Kelley, J. H.; Knörzer, M.; Pietralla, N.; Ponomarev, V. Yu.; Romig, C.; Scheck, M.; Scheit, H.; Silva, J.; Tonchev, A. P.; Tornow, W.; Weller, H. R.; Werner, V.; Zilges, A.; Zweidinger, M.

    2015-05-01

    The decay behavior of low-lying dipole states in 140Ce was investigated exploiting the γ3-setup at the HIγS facility using quasi-monochromatic photon beams. Branching ratios of individual excited states as well as average branching ratios to low-lying states have been extracted using γ - γ coincidence measurements. The comparison of the average branching ratios to QPM calculations shows a remarkable agreement between experiment and theory in the energy range from 5.0 to 8.5 MeV.

  6. Decay pattern of the Pygmy Dipole Resonance in 140Ce

    Directory of Open Access Journals (Sweden)

    Isaak J.

    2015-01-01

    Full Text Available The decay behavior of low-lying dipole states in 140Ce was investigated exploiting the γ3-setup at the HIγS facility using quasi-monochromatic photon beams. Branching ratios of individual excited states as well as average branching ratios to low-lying states have been extracted using γ – γ coincidence measurements. The comparison of the average branching ratios to QPM calculations shows a remarkable agreement between experiment and theory in the energy range from 5.0 to 8.5 MeV.

  7. Sub-wavelength metamaterial cylinders with multiple dipole resonances

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2009-01-01

    It has been shown that the sub-wavelength resonances of the individual MTM cylinders also occur for electrically small configurations combining 2 or 4 cylinders. For the 2-and 4-cylinder configurations the overall size is 1/20 and 1/12.5 of the smallest wavelength, respectively. These MTM...... configuration thus offer the possibility for multi-resonant electrically small configurations....

  8. Atomic many-body theory of giant resonances

    International Nuclear Information System (INIS)

    Kelly, H.P.; Altun, Z.

    1987-01-01

    In this paper the use of many-body perturbation theory (MBPT) to include effects of electron correlations is discussed. The various physical processes contributing to the broad photoionization cross sections of the rare gases are studied in terms of the relevant many-body diagrams. Use of the random phase approximation with exchange (RPAE) is discussed by Amusia and Cherepkov. Calculations using the relativistic RPAE are reviewed by Johnson. In addition, many-body perturbation theory (MBPT) is used to study resonances which are due to excitation of bound states degenerate with the continuum. Very interesting giant resonance structure can occur when an inner shell electron is excited into a vacant open-shell orbital of the same principal quantum number. A particular example which is studied is the neutral manganese atom 3p 6 3d 5 4s 2 ( 6 S), in which the spins of the five 3d electrons are aligned. A very large resonance occurs in the 3d and 4s cross sections due to 3p → 3d excitation near 51 eV, and calculations of this resonance by MBPT and RPAE are discussed. A second example of this type of resonance occurs in open-shell rare-earth atoms with configurations 4d 10 4f/sup n/5s 2 5p 6 s 2 . Calculations and experimental results will be discussed for the case of europium with a half-filled sub-shell 4f 7 . 71 references, 15 figures

  9. Structure and direct decay of Giant Monopole Resonances

    International Nuclear Information System (INIS)

    Avez, B.; Simenel, C.

    2013-01-01

    We study structure and direct decay of the Giant Monopole Resonance (GMR) at the Random Phase Approximation (RPA) level using the time-dependent energy density functional method in the linear response regime in a few doubly magic nuclei. A proper treatment of the continuum, through the use of large coordinate space, allows for a separation between the nucleus and its emitted nucleons. The microscopic structure of the GMR is investigated with the decomposition of the strength function into individual single-particle quantum numbers. A similar microscopic decomposition of the spectra of emitted nucleons by direct decay of the GMR is performed. In this harmonic picture of giant resonance, shifting every contribution by the initial single-particle energy allows to reconstruct the GMR strength function. The RPA residual interaction couples bound 1-particle 1-hole states to unbound ones, allowing for the total decay of the GMR. In this article, we then intend to get an understanding of the direct decay mechanism from coherent one-particle-one-hole superpositions, while neglecting more complex configurations. Time-dependent beyond mean-field approaches should be used, in the future, to extend this method. (orig.)

  10. Role of giant resonance excitation in heavy ion collisions

    International Nuclear Information System (INIS)

    Catara, F.; Chomaz, Ph.

    1987-01-01

    In this paper we discuss several aspects of heavy ion collisions involving collective vibrational modes. In our approach the relative motion is treated in a semiclassical approximation, while the intrinsic degrees of freedom are described microscopically within the RPA. The differences with respect to macroscopic models are analyzed in the appendix. First we present some results on the inelastic scattering cross section and we show that the structures observed experimentally can be explained in terms of multiple excitation of the Giant Quadrupole Resonance. After we calculate an adiabatic polarization potential describing the coupling to the collective vibrational modes and show that it produces a strong enhancement of the subbarrier fusion cross section. This enhancement is found to be enough to reproduce the experimental data for symmetric systems, while for asymmetric reactions the coupling to other degrees of freedom, like transfer, is needed. Finally we report some preliminary results on a dynamical calculation of the real and imaginary parts of the polarization potential. We show that at high incident energies (E/A > 20MeV) the role of the Giant Quadrupole Resonance becomes dominant

  11. The temperature dependence of giant resonances in high-excited nucleus

    International Nuclear Information System (INIS)

    Li Ming; Song Hongqiu

    1991-01-01

    The Hartree-Fock equation and the linear response theory in finite temperature are used to calculate the positions and transition strenghths of the giant resonances of high-excited nucleus Pb 208 . The result shows a downward shift and a broadening of the giant resonance energies as temperatrue increases

  12. Reaction theory for analysis of nuclear giant resonances production and decay processes

    International Nuclear Information System (INIS)

    Foglia, G.A.

    1991-01-01

    The existence of mixing parameters connected to the different decay forms of the giant resonances was theoretically justified, and their energy dependence determined as well using a reaction theory which treats in a consistent manner the giant multipolar resonances formation and their different decay modes. (L.C.J.A.)

  13. Spreading effects on the isovector dipole strength distribution in 208Pb

    International Nuclear Information System (INIS)

    Adachi, S.; Nguyen van Giai

    1984-01-01

    There is seemingly a difficulty with all Hartree-Fock RPA calculations to describe correctly the distribution of dipole strength in heavy nuclei above the giant dipole region. We investigate in a consistent framework the effects of damping into more complex configurations. We show that in 208 Pb, this damping leads to a smooth distribution at higher energies while it gives a satisfactory description of the spreading width of the giant dipole resonance. (orig.)

  14. The description of neutron and giant resonances within the quasiparticle-phonon nuclear model

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1978-01-01

    The general assumptions of the quasiparticle-phonon model of complex nuclei are given. The choice of the model Hamiltonian as an average field and residual forces is discussed. The phonon description and quasiparticle-phonon interaction are presented. The system of basic equations and their approximate solutions are obtained. The approximation is chosen so as to obtain the most correct description of few-quasiparticle components rather than of the whole wave function. The method of strength functions is presented, which plays a decisive role in practical realization of the quasiparticle-phonon model for the description of some properties of complex nuclei. The range of applicability of the quasiparticle-phonon nuclear model is determined as few-quasiparticle components of the wave functions at low, intermediate and high excitation energies averaged in a certain energy interval. The fragmentation of single-particle states in deformed nuclei is studied within this model. The dependence of neutron strength functions on the excitation energy is investigated for the transfer reactions of the type (d,p) and (d,t). The s - ,p - , and d-wave neutron strength functions are calculated at the neutron binding energy Bsub(n). A satisfactory agreement with experiment is obtained. A correct description of the radiative strength functions in spherical nuclei is obtained. The influence of the tail of the giant dipole resonance on the E1-strength functions is studied. The energies and EΛ-strength functions for giant multipole resonances in spherical and deformed nuclei are calculated. A correct description of their widths is obtained. (author)

  15. Semiclassical approach to giant resonances of rotating nuclei

    International Nuclear Information System (INIS)

    Winter, J.

    1983-01-01

    Quadrupole and isovector dipole resonances of rotating nuclei are investigated in the frame-work of Vlasov equations transformed to a rotating system of reference, which are based on the time-dependent Hartree-method for schematic forces. The parameter free model of the self-consistent vibrating harmonic oscillator potential for the quadrupole mode is extended to a coupling to rotation, which also includes large-amplitude behaviour. A generalization to an exactly solvable two-liquid model describing the isovector mode is established; for rotating nuclei Hilton's explicit result for the eigenfrequencies is obtained. The advantage of using the concept of the classical kinetic momentum in a rotating system also in quantum-mechanical descriptions is demonstrated. It completes the standard transformation of density matrices by a time-odd part realized in a phase-factor and permits a more direct interpretation of rotation effects in terms of the classical forces of inertia. (author)

  16. On some aspects of the semiclassical approach to giant resonances of rotating nuclei

    International Nuclear Information System (INIS)

    Winter, J.

    1985-01-01

    Quadrupole and isovector dipole resonances of rotating nuclei are investigated in the frame-work of Vlasov equations transformed to a rotating system of reference, which are based on the time-dependent Hartree-method for schematic forces. The parameter free model of the self-consistent vibrating harmonic oscillator potential for the quadrupole mode is extended to a coupling to rotation, which also includes large amplitude behaviour. A generalization to an exactly solvable two-liquid model describing the isovector mode is established; for rotating nuclei Hilton's explicit result for the eigenfrequencies is obtained. - The advantage of using the concept of the classical kinetic momentum in a rotating system also in quantum-mechanical descriptions is demonstrated. It completes the standard transformation of density matrices by a time-odd part realized in a phase-factor and permits a more direct interpretation of rotation effects in terms of the classical forces of inertia. - In its generalization from constant angular velocity to constant angular momentum, our model is used to demonstrate that cranking calculations of rotating giant resonances should be corrected for an oscillation of the cranking parameter to assure angular-momentum conservation. (orig.)

  17. b-dipole transitions in trans-HOCO observed by far infrared laser magnetic resonance

    International Nuclear Information System (INIS)

    Sears, T.J.; Radford, H.E.; Moore, M.A.

    1993-01-01

    Far infrared laser magnetic resonance spectroscopy is used to measure components of 12 rotational transitions in the ground state of the HOCO radical. The transitions are all b-dipole in character in contrast to the a-dipole rotational spectrum previously reported [Radford, Wei, and Sears, J. Chem. Phys. 97, 3989 (1992)]. The new data determine the A rotational constant to high precision and allow the determination of several centrifugal distortion constants for the first time. The hyperfine coupling in the radical leads to observable splittings in several of the observed transitions and these are used to estimate two of the four expected nonzero hyperfine parameters in the radical

  18. The decay pattern of the Pygmy Dipole Resonance of 140Ce

    Science.gov (United States)

    Löher, B.; Savran, D.; Aumann, T.; Beller, J.; Bhike, M.; Cooper, N.; Derya, V.; Duchêne, M.; Endres, J.; Hennig, A.; Humby, P.; Isaak, J.; Kelley, J. H.; Knörzer, M.; Pietralla, N.; Ponomarev, V. Yu.; Romig, C.; Scheck, M.; Scheit, H.; Silva, J.; Tonchev, A. P.; Tornow, W.; Wamers, F.; Weller, H.; Werner, V.; Zilges, A.

    2016-05-01

    The decay properties of the Pygmy Dipole Resonance (PDR) have been investigated in the semi-magic N = 82 nucleus 140Ce using a novel combination of nuclear resonance fluorescence and γ-γ coincidence techniques. Branching ratios for transitions to low-lying excited states are determined in a direct and model-independent way both for individual excited states and for excitation energy intervals. Comparison of the experimental results to microscopic calculations in the quasi-particle phonon model exhibits an excellent agreement, supporting the observation that the Pygmy Dipole Resonance couples to the ground state as well as to low-lying excited states. A 10% mixing of the PDR and the [21+ × PDR ] is extracted.

  19. The decay pattern of the Pygmy Dipole Resonance of 140Ce

    Directory of Open Access Journals (Sweden)

    B. Löher

    2016-05-01

    Full Text Available The decay properties of the Pygmy Dipole Resonance (PDR have been investigated in the semi-magic N=82 nucleus 140Ce using a novel combination of nuclear resonance fluorescence and γ–γ coincidence techniques. Branching ratios for transitions to low-lying excited states are determined in a direct and model-independent way both for individual excited states and for excitation energy intervals. Comparison of the experimental results to microscopic calculations in the quasi-particle phonon model exhibits an excellent agreement, supporting the observation that the Pygmy Dipole Resonance couples to the ground state as well as to low-lying excited states. A 10% mixing of the PDR and the [21+×PDR] is extracted.

  20. Outward Migration of Giant Planets in Orbital Resonance

    Science.gov (United States)

    D'Angelo, G.; Marzari, F.

    2013-05-01

    A pair of giant planets interacting with a gaseous disk may be subject to convergent orbital migration and become locked into a mean motion resonance. If the orbits are close enough, the tidal gaps produced by the planets in the disk may overlap. This represents a necessary condition to activate the outward migration of the pair. However, a number of other conditions must also be realized in order for this mechanism to operate. We have studied how disk properties, such as turbulence viscosity, temperature, surface density gradient, mass, and age, may affect the outcome of the outward migration process. We have also investigated the implications on this mechanism of the planets' gas accretion. If the pair resembles Jupiter and Saturn, the 3:2 orbital resonance may drive them outward until they reach stalling radii for migration, which are within ~10 AU of the star for disks representative of the early proto-solar nebula. However, planet post-formation conditions in the disk indicate that such planets become typically locked in the 1:2 orbital resonance, which does not lead to outward migration. Planet growth via gas accretion tends to alter the planets' mass-ratio and/or the disk accretion rate toward the star, reducing or inhibiting outward migration. Support from NASA Outer Planets Research Program and NASA Origins of Solar Systems Program is gratefully acknowledged.

  1. Electric Dipole States and Time Reversal Violation in Nuclei

    International Nuclear Information System (INIS)

    Auerbach, N.

    2016-01-01

    The nuclear Schiff moment is essential in the mechanism that induces a parity and time reversal violation in the atom. In this presentation we explore theoretically the properties and systematics of the isoscalar dipole in nuclei with the emphasis on the low-energy strength and the inverse energy weighted sum which determines the Schiff moment. We also study the influence of the isovector dipole strength distribution on the Schiff moment. The influence of a large neutron excess in nuclei is examined. The centroid energies of the isoscalar giant resonance (ISGDR) and the overtone of the isovector giant dipole resonance (OIVGDR) are given for a range of nuclei. (paper)

  2. Charge-exchange giant resonances as probes of nuclear structure

    International Nuclear Information System (INIS)

    Blomgren, J.

    2001-09-01

    Giant resonances populated in charge-exchange reactions can reveal detailed information about nuclear structure properties, in spite of their apparent featurelessness. The (p,n) and (n,p) reactions - as well as their analog reactions - proceed via the same nuclear matrix element as beta decay. Thereby, they are useful for probing electroweak properties in nuclei, especially for those not accessible to beta decay. The nuclear physics aspects of double beta decay might be investigated in double charge-exchange reactions. detailed nuclear structure information, such as the presence of ground-state correlations, can be revealed via identification of 'first-forbidden' transitions. In addition, astrophysics aspects and halo properties of nuclei have been investigated in charge exchange. Finally, these experiments have questioned our knowledge of the absolute strength of the strong interaction

  3. The giant quadrupole resonance in highly excited rotating nuclei

    International Nuclear Information System (INIS)

    Civitarese, O.; Furui, S.; Ploszajczak, M.; Faessler, A.

    1983-01-01

    The giant quadrupole resonance in highly excited, fast rotating nuclei is studied as a function of both the nuclear temperature and the nuclear angular momentum. The photo-absorption cross sections for quadrupole radiation in 156 Dy, 160 Er and 164 Er are evaluated within the linear response theory. The strength functions of the γ-ray spectrum obtained from the decay of highly excited nuclear states by deexcitation of the isoscalar quadrupole mode show a fine structure, which depends on the temperature T, the angular momentum I and the deformation of the nucleus β. The splitting of the modes associated with the signature-conserving and signature-changing components of the quadrupole field is discussed. (orig.)

  4. Phase-space exploration in nuclear giant resonance decay

    International Nuclear Information System (INIS)

    Drozdz, S.; Nishizaki, S.; Wambach, J.; Speth, J.

    1995-01-01

    The rate of phase-space exploration in the decay of isovector and isoscalar giant quadrupole resonances in 40 Ca is analyzed. The study is based on the time dependence of the survival probability and of the spectrum of generalized entropies evaluated in the space of one-particle--one-hole (1p-1h) and 2p-2h states. Three different cases for the level distribution of 2p-2h background states, corresponding to (a) high degeneracy, (b) classically regular motion, and (c) classically chaotic motion, are studied. In the latter case the isovector excitation evolves almost statistically while the isoscalar excitation remains largely localized, even though it penetrates the whole available phase space

  5. Optical resonator for a standing wave dipole trap for fermionic lithium atoms

    International Nuclear Information System (INIS)

    Elsaesser, T.

    2000-01-01

    This thesis reports on the the construction of an optical resonator for a new resonator dipole trap to store the fermionic 6 Li-isotope and to investigate its scattering properties. It was demonstrated that the resonator enhances the energy density of a (1064 nm and 40 mW) laser beam by a factor of more than 100. A fused silica vacuum cell is positioned inside the resonator under Brewster's angle. The losses of the resonator depend mainly on the optical quality of the cell. The expected trap depth of the dipole trap is 200 μK and the photon scattering rate is expected to be about 0.4 s -1 . The resonator is stabilized by means of a polarization spectroscopy method. Due to high trap frequencies, which are produced by the tight enclosure of the standing wave in the resonator, the axial motion must be quantized. A simple model to describe this quantization has been developed. A magneto-optical trap, which serves as a source of cold lithium atoms, was put in operation. (orig.)

  6. Electric giant resonances in sup 4 sup 0 Ca and sup 4 sup 8 Ca probed with electron and proton scattering coincidence experiments

    CERN Document Server

    Strauch, S

    1999-01-01

    Excitation and particle decay of electric giant resonances in sup 4 sup 0 Ca and sup 4 sup 8 Ca are studied with electron and proton beams. Recent results of a sup 4 sup 8 Ca(e,e'n) measurement performed at the S-DALINAC in Darmstadt with kinematics that selectively populate electric monopole, dipole and quadrupole excitations are presented. The extracted B(E1) strength distribution is in good agreement with photo nuclear data and the predictions of microscopic calculations. The summed B(E2+E0) strength distribution, however disagrees with the result of these calculations. The neutron emission of the giant dipole resonance in sup 4 sup 8 Ca shows a large fraction of direct decay to sup 4 sup 7 Ca hole states. In addition, isoscalar giant monopole resonance strength in sup 4 sup 0 Ca was extracted from (e,e'alpha sub 0) and (e,e'alpha sub 1) angular correlations. A study of the quadrupole strength in the alpha sub 0 decay channel of sup 4 sup 0 Ca with a (p,p'alpha) coincidence measurement reiterates the unsol...

  7. Dephasing due to Nuclear Spins in Large-Amplitude Electric Dipole Spin Resonance.

    Science.gov (United States)

    Chesi, Stefano; Yang, Li-Ping; Loss, Daniel

    2016-02-12

    We analyze effects of the hyperfine interaction on electric dipole spin resonance when the amplitude of the quantum-dot motion becomes comparable or larger than the quantum dot's size. Away from the well-known small-drive regime, the important role played by transverse nuclear fluctuations leads to a Gaussian decay with characteristic dependence on drive strength and detuning. A characterization of spin-flip gate fidelity, in the presence of such additional drive-dependent dephasing, shows that vanishingly small errors can still be achieved at sufficiently large amplitudes. Based on our theory, we analyze recent electric dipole spin resonance experiments relying on spin-orbit interactions or the slanting field of a micromagnet. We find that such experiments are already in a regime with significant effects of transverse nuclear fluctuations and the form of decay of the Rabi oscillations can be reproduced well by our theory.

  8. Derivative corrections to the symmetry energy and the isovector dipole-resonance structure in nuclei

    International Nuclear Information System (INIS)

    Blocki, J P; Magner, A G; Ring, P

    2015-01-01

    The effective surface approximation is extended accounting for derivatives of the symmetry energy density per particle. The new expressions for the isovector surface energy constants are used for calculations of improved energies and sum rules of the isovector dipole-resonance strength structure within the Fermi-liquid droplet model. Our results are in reasonable agreement with experimental data and with other theoretical approaches. (paper)

  9. Vibrational Fano resonances in the photodetachment of dipole-bound anions

    International Nuclear Information System (INIS)

    Edwards, Stephen T; Tully, John C; Johnson, Mark A

    2012-01-01

    A simple model for the photodetachment of dipole-bound anions is proposed where non-adiabatic coupling of vibrational states leads to a Fano resonance in the spectrum. It is found that the shape of the photodetachment spectrum depends significantly on the parameter representing molecular polarizability. The model is also applied to a Fano profile observed in the photodetachment of small water cluster anions.

  10. Strength function for the giant isovector monopole resonance

    International Nuclear Information System (INIS)

    MacDonald, W.M.; Birse, M.C.

    1984-01-01

    The theory of the strength function for giant resonances is extended to exhibit the explicit energy dependence of the width and shift functions for the giant isovector monopole. An integral sum rule on the width GAMMA/sub M/(E) relates its normalization to the second moment M 2 of the strength function and leads to a relation GAMMA/sub M/(E/sub M/)GAMMA/sub s//4 = M 2 between M 2 and the width at the maximum, which involves the width GAMMA/sub s/ of the distribution in energy of the spreading matrix elements. An estimate of GAMMA/sub M/(E/sub M/)approx. =8 MeV based on the absorptive part of the optical potential together with random-phase approximation calculations of M 2 leads to the result GAMMA/sub s//2approx. =2hω, supporting the intermediate coupling model of Lane, Thomas, and Wigner. Using the sum rule expressions of Lane and Mekjian to evaluate the Coulomb matrix element M/sub A/M between an isobaric analog state and its corresponding isovector monopole, we test this strength function for the isovector monopole by calculating the spreading widths for the ground state analogs of nuclei from 38 Cl to 208 Pb. The good agreement with the systematic dependence upon mass number and isospin resolves the long-standing discrepancy between the estimate GAMMA/sub M/(E/sub M/)approx.8--10 MeV and the value GAMMA/sub M/(E/sub A/)< or =2 MeV needed to account for the spreading widths of the isobaric analog state

  11. Photoionization of lanthanum and its ions in the region of the 'giant' resonance

    International Nuclear Information System (INIS)

    Amusia, M.Ya.

    1989-01-01

    The photoionization cross sections of outer and intermediate shells including 4d of La and its ions are calculated in the region of the 'giant' resonance. The prominent effects of both intershell correlational effects and rearrangement are demonstrated. (orig.)

  12. Inelastic scattering of 9Be of 27 MeV/A to giant resonances

    International Nuclear Information System (INIS)

    Lebrun, D.; Buenerd, M.; Bini, M.; Harvey, B.G.; Legrain, R.; Mahoney, J.; Symons, T.J.M.; Van Bibber, K.

    1980-07-01

    Inelastic scattering spectra have been measured with 245 MeV incident energy 9 Be ions, on 208 Pb target. They show large excitation of the 208 Pb giant quadrupole resonance. DWBA calculations are reported and compared with the data

  13. Magnetic dipole strength in {sup 128}Xe and {sup 134}Xe in the spin-flip resonance region

    Energy Technology Data Exchange (ETDEWEB)

    Massarczyk, R. [Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Rusev, G. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Schwengner, R.; Doenau, F. [Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Bathia, C. [McMaster University, Hamilton, Ontario L8S4L8 (Canada); Gooden, M.E.; Kelley, J.H. [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); North Carolina State University, Raleigh, NC 27695 (United States); Tonchev, A.P. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Tornow, W. [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Duke University, Durham, NC 27708 (United States)

    2015-07-01

    The magnetic dipole strength in the energy region of the spin-flip resonance is investigated in {sup 128}Xe and {sup 134}Xe using quasimonoenergetic and linearly polarized γ-ray beams at the High-Intensity γ-Ray Source facility in Durham, North Carolina, USA. Absorption cross sections were deduced for the magnetic and electric and dipole strength distributions separately for various intervals of excitation energy, including the strength of states in the unresolved quasicontinuum. The magnetic dipole strength distributions show structures resembling a resonance in the spin-flip region around an excitation energy of 8 MeV. The electric dipole strength distributions obtained from the present experiments are in agreement with the ones deduced from an earlier experiment using broad-band bremsstrahlung instead of a quasimonoenergetic beam. The experimental magnetic and electric dipole strength distributions are compared with model predictions.

  14. (p,n) and (n,p) reactions as probes of isovector giant monopole resonances

    International Nuclear Information System (INIS)

    Auerbach, N.; Bowman, J.D.; Franey, M.A.; Love, W.G.

    1983-01-01

    Nucleon charge exchange reactions are explored as prospective probes of isovector giant monopole resonances. Using charge exchange transition densities based on random-phase approximation sum rules, distorted wave impulse approximation calculations are made for the (p,n) and (n,p) reactions exciting the isovector giant monopole resonances in several nuclei at bombarding energies of 120 and 800 MeV. Based on our calculations, the charge exchange reactions at 800 MeV appear more promising

  15. Spectroscopic factors of the alpha decay of isoscalar giant resonances

    International Nuclear Information System (INIS)

    Smirnov, Yu.F.; Chuvil'skij, Yu.M.

    1983-01-01

    A system which enables to connect Ssub(α) spectroscopic factors (SF) for α-decay of the isoscalar giant resonance (GR) states E0 and E2 with SF values for ground and low lying nucleus states has been developed. This method permits to consider initial nucleus GR decay with a transition to the residual nucleus-GR. It is necessary to know only SF for GR decay to the daughter nucleus ground state with the emission of an excited cluster in the common case. The above method is based on properties of infinitesimal operators of Sp(2, R), Sp(6, R) groups and uses SU(3)-symmetry of wave functions of initial nucleus, cluster and residual nucleus, Values of ratios of α-particle SF are presented for 8 Be, HH2C, 16 O, 20 Ne, 24 Mg, 28 Si, 40 Ca, 44 Ti nuclei and Ssub(α) transitions to GR states of residual nucleus for 16 O, 20 Ne and 40 Ca nuclei. Noticeable Ssub(α) values for virtual α-decay of an initial nucleus ground state to residual nucleus GR poins out that α-particle knock out processes may be also accompanied by the final nucleus GR excitation

  16. Giant quadrupole resonance in 12C, 24Mg, and 27Al observed via deuteron inelastic scattering

    International Nuclear Information System (INIS)

    Chang, C.C.; Didelez, J.P.; Kwiatowski, K.; Wo, J.R.

    1977-06-01

    Giant quadrupole resonance in 12 C, 24 Mg, and 27 Al was studied using 70 MeV deuteron beam. The results clearly show, in all three targets, resonance-like structures peaked at E/sub x/ approximately 63A/sup -1/3/ MeV, with a width of about 10 MeV. The experimental angular distributions for these resonances agree well with the l = 2 DWBA prediction. For 12 C, a binary splitting was observed, and for 24 Mg, there are indications of finer structure in the main giant quadrupole resonance region

  17. TESTING CONVECTIVE-CORE OVERSHOOTING USING PERIOD SPACINGS OF DIPOLE MODES IN RED GIANTS

    Energy Technology Data Exchange (ETDEWEB)

    Montalban, J.; Noels, A.; Dupret, M.-A.; Scuflaire, R. [Institut d' Astrophysique et Geophysique de l' Universite de Liege, Allee du six Aout, 17 B-4000 Liege (Belgium); Miglio, A. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Ventura, P. [Osservatorio Astronomico di Roma-INAF, via Frascati 33, I-00040 Monteporzio Catone, Rome (Italy)

    2013-04-01

    Uncertainties on central mixing in main-sequence (MS) and core He-burning (He-B) phases affect key predictions of stellar evolution such as late evolutionary phases, chemical enrichment, ages, etc. We propose a test of the extension of extra-mixing in two relevant evolutionary phases based on period spacing ({Delta}P) of solar-like oscillating giants. From stellar models and their corresponding adiabatic frequencies (respectively, computed with ATON and LOSC codes), we provide the first predictions of the observable {Delta}P for stars in the red giant branch and in the red clump (RC). We find (1) a clear correlation between {Delta}P and the mass of the helium core (M{sub He}); the latter in intermediate-mass stars depends on the MS overshooting, and hence it can be used to set constraints on extra-mixing during MS when coupled with chemical composition; and (2) a linear dependence of the average value of the asymptotic period spacing (({Delta}P){sub a}) on the size of the convective core during the He-B phase. A first comparison with the inferred asymptotic period spacing for Kepler RC stars also suggests the need for extra-mixing during this phase, as evinced from other observational facts.

  18. The dipole response of {sup 132}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Schrock, Philipp; Aumann, Thomas; Johansen, Jacob; Schindler, Fabia [IKP, TU Darmstadt (Germany); Boretzky, Konstanze [GSI Helmholtzzentrum (Germany); Rossi, Dominic [Michigan State University (United States); Collaboration: R3B-Collaboration

    2015-07-01

    The Isovector Giant Dipole Resonance (IVGDR) is a well-known collective excitation in which all protons oscillate against all neutrons of a nucleus. In neutron-rich nuclei an additional low-lying dipole excitation occurs, often denoted as Pygmy Dipole Resonance (PDR). To study the PDR in exotic Sn-isotopes, an experiment has been successfully performed with the upgraded R{sup 3}B-LAND setup at GSI. The complete-kinematics measurement of all reaction participants allows for the reconstuction of the excitation energy and, hence, the extraction of the dipole strength. Presented are the main features of the experiment, the analysis concept and the current status of the analysis of the dipole response of the doubly-magic isotope {sup 132}Sn.

  19. Isoscalar giant resonances and Landau parameters with density-dependent effective interactions

    International Nuclear Information System (INIS)

    Kohno, Michio; Ando, Kazuhiko

    1979-01-01

    Discussion is given on the relations between the Landau parameters and the isoscalar giant (quadrupole- and monopole-) resonance energies by using general density-dependent interactions. In the limit of infinite nuclear matter, the isoscalar giant quadrupole energy is shown to depend not only on the effective mass but also on the Landau parameter F 2 . Collective energies of the isoscalar giant resonances are calculated for 16 O and 40 Ca with four different effective interactions, G-0, B1, SII and SV, by using the scaling- and constrained Hartree-Fock-methods. It is shown that the dependence of the collective energies on the effective interactions is essentially determined by the Landau parameters. The G-0 force is found to be most successful in reproducing the giant resonance energies. Validity of the RPA-moment theorems is examined for the case of local density-dependent interactions. (author)

  20. Spin-orbit coupling and electric-dipole spin resonance in a nanowire double quantum dot.

    Science.gov (United States)

    Liu, Zhi-Hai; Li, Rui; Hu, Xuedong; You, J Q

    2018-02-02

    We study the electric-dipole transitions for a single electron in a double quantum dot located in a semiconductor nanowire. Enabled by spin-orbit coupling (SOC), electric-dipole spin resonance (EDSR) for such an electron can be generated via two mechanisms: the SOC-induced intradot pseudospin states mixing and the interdot spin-flipped tunneling. The EDSR frequency and strength are determined by these mechanisms together. For both mechanisms the electric-dipole transition rates are strongly dependent on the external magnetic field. Their competition can be revealed by increasing the magnetic field and/or the interdot distance for the double dot. To clarify whether the strong SOC significantly impact the electron state coherence, we also calculate relaxations from excited levels via phonon emission. We show that spin-flip relaxations can be effectively suppressed by the phonon bottleneck effect even at relatively low magnetic fields because of the very large g-factor of strong SOC materials such as InSb.

  1. Giant Cu 2p Resonances in CuO Valence-Band Photoemission

    NARCIS (Netherlands)

    Tjeng, L.H.; Chen, C.T.; Ghijsen, J.; Rudolf, P.; Sette, F.

    1991-01-01

    We report the observation of a giant resonance in the Cu 2p resonant-photoemission spectra of CuO. The study allows the unambiguous identification of the local Cu 3d8 configuration in the valence-band photoemission spectrum, providing conclusive evidence for the charge-transfer nature of the

  2. Collisional damping of giant monopole and quadrupole resonances

    International Nuclear Information System (INIS)

    Yildirim, S.; Gokalp, A.; Yilmaz, O.; Ayik, S.

    2001-01-01

    Collisional damping widths of giant monopole and quadrupole excitations for 120 Sn and 208 Pb at zero and finite temperatures are calculated within Thomas-Fermi approximation by employing the microscopic in-medium cross-sections of Li and Machleidt and the phenomenological Skyrme and Gogny forces, and are compared with each other. The results for the collisional widths of giant monopole and quadrupole vibrations at zero temperature as a function of the mass number show that the collisional damping of giant monopole vibrations accounts for about 30 - 40% of the observed widths at zero temperature, while for giant quadrupole vibrations it accounts for only 20 - 30% of the observed widths at zero temperature. (orig.)

  3. Electric dipole spin resonance in a quantum spin dimer system driven by magnetoelectric coupling

    Science.gov (United States)

    Kimura, Shojiro; Matsumoto, Masashige; Akaki, Mitsuru; Hagiwara, Masayuki; Kindo, Koichi; Tanaka, Hidekazu

    2018-04-01

    In this Rapid Communication, we propose a mechanism for electric dipole active spin resonance caused by spin-dependent electric polarization in a quantum spin gapped system. This proposal was successfully confirmed by high-frequency electron spin resonance (ESR) measurements of the quantum spin dimer system KCuCl3. ESR measurements by an illuminating linearly polarized electromagnetic wave reveal that the optical transition between the singlet and triplet states in KCuCl3 is driven by an ac electric field. The selection rule of the observed transition agrees with the calculation by taking into account spin-dependent electric polarization. We suggest that spin-dependent electric polarization is effective in achieving fast control of quantum spins by an ac electric field.

  4. Dipole-resonance assisted isomerization in the electronic ground state using few-cycle infrared pulses.

    Science.gov (United States)

    Skocek, Oliver; Uiberacker, Christoph; Jakubetz, Werner

    2011-06-30

    A computational investigation of HCN → HNC isomerization in the electronic ground state by one- and few-cycle infrared pulses is presented. Starting from a vibrationally pre-excited reagent state, isomerization yields of more than 50% are obtained using single one- to five-cycle pulses. The principal mechanism includes two steps of population transfer by dipole-resonance (DR), and hence, the success of the method is closely linked to the polarity of the system and, in particular, the stepwise change of the dipole moment from reactant to transition state and on to products. The yield drops massively if the diagonal dipole matrix elements are artificially set to zero. In detail, the mechanism includes DR-induced preparation of a delocalized vibrational wavepacket, which traverses the barrier region and is finally trapped in the product well by DR-dominated de-excitation. The excitation and de-excitation steps are triggered by pulse lobes of opposite field direction. As the number of optical cycles is increased, the leading field lobes prepare a vibrational superposition state by off-resonant ladder climbing, which is then subjected to the three steps of the principal isomerization mechanism. DR excitation is more efficient from a preformed vibrational wavepacket than from a molecular eigenstate. The entire process can be loosely described as Tannor-Kosloff-Rice type transfer mechanism on a single potential surface effected by a single pulse, individual field lobes assuming the roles of pump- and dump-pulses. Pre-excitation to a transient wavepacket can be enhanced by applying a separate, comparatively weak few-cycle prepulse, in which the prepulse prepares a vibrational wavepacket. The two-pulse setup corresponds to a double Tannor-Kosloff-Rice control scheme on a single potential surface.

  5. Precision polarization measurements of atoms in a far-off-resonance optical dipole trap

    International Nuclear Information System (INIS)

    Fang, F.; Vieira, D. J.; Zhao, X.

    2011-01-01

    Precision measurement of atomic and nuclear polarization is an essential step for beta-asymmetry measurement of radioactive atoms. In this paper, we report the polarization measurement of Rb atoms in an yttrium-aluminum-garnet (YAG) far-off-resonance optical dipole trap. We have prepared a cold cloud of polarized Rb atoms in the YAG dipole trap by optical pumping and achieved an initial nuclear polarization of up to 97.2(5)%. The initial atom distribution in different Zeeman levels is measured by using a combination of microwave excitation, laser pushing, and atomic retrap techniques. The nuclear-spin polarization is further purified to 99.2(2)% in 10 s and maintained above 99% because the two-body collision loss rate between atoms in mixed spin states is greater than the one-body trap loss rate. Systematic effects on the nuclear polarization, including the off-resonance Raman scattering, magnetic field gradient, and background gas collisions, are discussed.

  6. Decay of giant resonance E2 isoscalar in heavy nuclei. Decaimento da ressonancia gigante E2 isoescalar em nucleos pesados

    Energy Technology Data Exchange (ETDEWEB)

    Herdade, S B [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

    1980-01-01

    In this work, it is made a study of the giant resonance E2 isoscalar, in heavy nuclei. Fission probabilities for this resonance were determined by various authors, in different experiments, for {sup 238}U. (A.C.A.S.).

  7. Deformation-induced splitting of the monopole giant resonance in 24Mg

    Directory of Open Access Journals (Sweden)

    Kvasil J.

    2016-01-01

    Full Text Available The strong deformation splitting of the isoscalar giant monopole resonance (ISGMR, recently observed in (α, α′ reaction in prolate 24Mg, is analyzed in the framework of the Skyrme quasiparticle randomphase-approximation (QRPA approach with the Skyrme forces SkM*, SVbas and SkPδ. The calculations with these forces give close results and confirm that the low-energy E0-peak is caused by the deformation-induced coupling of ISGMR with the K = 0 branch of the isoscalar giant quadrupole resonance.

  8. Sum rule approach to the study of statistical decay properties of nuclear giant resonances

    International Nuclear Information System (INIS)

    Adhikari, S.K.; Hussein, M.S.

    1987-03-01

    Corrections to the well-known statistical sum rule that relates the summed transmission coefficients on the one hand and 2πΓ C.N. .ρ C.N. On the other, in the context of the statistical decay properties of nuclear giant resonances, are discussed. These corrections arise both from pre-equilibrium processes as well as from the giant resonance itself. It is shown that the compound nucleus average width is reduced as a result of these corrections. (Author) [pt

  9. Photoresponse of 60Ni below 10-MeV excitation energy: Evolution of dipole resonances in fp-shell nuclei near N=Z

    Science.gov (United States)

    Scheck, M.; Ponomarev, V. Yu.; Fritzsche, M.; Joubert, J.; Aumann, T.; Beller, J.; Isaak, J.; Kelley, J. H.; Kwan, E.; Pietralla, N.; Raut, R.; Romig, C.; Rusev, G.; Savran, D.; Schorrenberger, L.; Sonnabend, K.; Tonchev, A. P.; Tornow, W.; Weller, H. R.; Zilges, A.; Zweidinger, M.

    2013-10-01

    Background: Within the last decade, below the giant dipole resonance the existence of a concentration of additional electric dipole strength has been established. This accumulation of low-lying E1 strength is commonly referred to as pygmy dipole resonance (PDR).Purpose: The photoresponse of 60Ni has been investigated experimentally and theoretically to test the evolution of the PDR in a nucleus with only a small neutron excess. Furthermore, the isoscalar and isovector M1 resonances were investigated.Method: Spin-1 states were excited by exploiting the (γ,γ') nuclear resonance fluorescence technique with unpolarized continuous bremsstrahlung as well as with fully linearly polarized, quasimonochromatic, Compton-backscattered laser photons in the entrance channel of the reaction.Results: Up to 10 MeV a detailed picture of J=1 levels was obtained. For the preponderant number of the individual levels spin and parity were firmly assigned. Furthermore, branching ratios, transition widths, and reduced B(E1) or B(M1) excitation probability were calculated from the measured scattering cross sections. A comparison with theoretical results obtained within the quasiparticle phonon model allows an insight into the microscopic structure of the observed states.Conclusions: Below 10 MeV the directly observed E1 strength [∑B(E1)↑=(153.8±9.5) e2(fm)2] exhausts 0.5% of the Thomas-Reiche-Kuhn sum rule. This value increases to 0.8% of the sum rule [∑B(E1)↑=(250.9±31.1) e2(fm)2] when indirectly observed branches to lower-lying levels are considered. Two accumulations of M1 excited spin-1 states near 8 and 9 MeV excitation energy are identified as isoscalar and isovector M1 resonances dominated by proton and neutron f7/2→f5/2 spin-flip excitations. The B(M1)↑ strength of these structures accumulates to 3.94(27)μN2.

  10. General classical and quantum-mechanical description of magnetic resonance: an application to electric-dipole-moment experiments

    Energy Technology Data Exchange (ETDEWEB)

    Silenko, Alexander J. [Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); Joint Institute for Nuclear Research, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation)

    2017-05-15

    A general theoretical description of a magnetic resonance is presented. This description is necessary for a detailed analysis of spin dynamics in electric-dipole-moment experiments in storage rings. General formulas describing a behavior of all components of the polarization vector at the magnetic resonance are obtained for an arbitrary initial polarization. These formulas are exact on condition that the nonresonance rotating field is neglected. The spin dynamics is also calculated at frequencies far from resonance with allowance for both rotating fields. A general quantum-mechanical analysis of the spin evolution at the magnetic resonance is fulfilled and the full agreement between the classical and quantum-mechanical approaches is shown. Quasimagnetic resonances for particles and nuclei moving in noncontinuous perturbing fields of accelerators and storage rings are considered. Distinguishing features of quasimagnetic resonances in storage ring electric-dipole-moment experiments are investigated in detail. The exact formulas for the effect caused by the electric dipole moment are derived. The difference between the resonance effects conditioned by the rf electric-field flipper and the rf Wien filter is found and is calculated for the first time. The existence of this difference is crucial for the establishment of a consent between analytical derivations and computer simulations and for checking spin tracking programs. The main systematical errors are considered. (orig.)

  11. Hyperfine interaction mediated electric-dipole spin resonance: the role of frequency modulation

    International Nuclear Information System (INIS)

    Li, Rui

    2016-01-01

    The electron spin in a semiconductor quantum dot can be coherently controlled by an external electric field, an effect called electric-dipole spin resonance (EDSR). Several mechanisms can give rise to the EDSR effect, among which there is a hyperfine mechanism, where the spin-electric coupling is mediated by the electron–nucleus hyperfine interaction. Here, we investigate the influence of frequency modulation (FM) on the spin-flip efficiency. Our results reveal that FM plays an important role in the hyperfine mechanism. Without FM, the electric field almost cannot flip the electron spin; the spin-flip probability is only about 20%. While under FM, the spin-flip probability can be improved to approximately 70%. In particular, we find that the modulation amplitude has a lower bound, which is related to the width of the fluctuated hyperfine field. (paper)

  12. Test of the Brink-Axel Hypothesis for the Pygmy Dipole Resonance

    Science.gov (United States)

    Martin, D.; von Neumann-Cosel, P.; Tamii, A.; Aoi, N.; Bassauer, S.; Bertulani, C. A.; Carter, J.; Donaldson, L.; Fujita, H.; Fujita, Y.; Hashimoto, T.; Hatanaka, K.; Ito, T.; Krugmann, A.; Liu, B.; Maeda, Y.; Miki, K.; Neveling, R.; Pietralla, N.; Poltoratska, I.; Ponomarev, V. Yu.; Richter, A.; Shima, T.; Yamamoto, T.; Zweidinger, M.

    2017-11-01

    The gamma strength function and level density of 1- states in 96Mo have been extracted from a high-resolution study of the (p → , p→ ' ) reaction at 295 MeV and extreme forward angles. By comparison with compound nucleus γ decay experiments, this allows a test of the generalized Brink-Axel hypothesis in the energy region of the pygmy dipole resonance. The Brink-Axel hypothesis is commonly assumed in astrophysical reaction network calculations and states that the gamma strength function in nuclei is independent of the structure of the initial and final state. The present results validate the Brink-Axel hypothesis for 96Mo and provide independent confirmation of the methods used to separate gamma strength function and level density in γ decay experiments.

  13. Nuclear spin cooling by electric dipole spin resonance and coherent population trapping

    Science.gov (United States)

    Li, Ai-Xian; Duan, Su-Qing; Zhang, Wei

    2017-09-01

    Nuclear spin fluctuation suppression is a key issue in preserving electron coherence for quantum information/computation. We propose an efficient way of nuclear spin cooling in semiconductor quantum dots (QDs) by the coherent population trapping (CPT) and the electric dipole spin resonance (EDSR) induced by optical fields and ac electric fields. The EDSR can enhance the spin flip-flop rate and may bring out bistability under certain conditions. By tuning the optical fields, we can avoid the EDSR induced bistability and obtain highly polarized nuclear spin state, which results in long electron coherence time. With the help of CPT and EDSR, an enhancement of 1500 times of the electron coherence time can been obtained after a 500 ns preparation time.

  14. Microscopic studies of electric dipole resonances in 1p shell nuclei

    International Nuclear Information System (INIS)

    Kissener, H.R.; Rotter, I.; Goncharova, N.G.

    1986-05-01

    Recent data on total and partial photonuclear cross sections in the GDR region of the nuclei 6 Li to 16 O are compared with theoretical predictions, mostly from shell model and continuum shell model studies. The influence of the size of the configuration space, of the adopted residual interaction and of the continuous spectrum on the isovector E1 response is discussed to some detail. The observed trends of the localization, the shape and width, the isospin and the configurational structure of the GDR with increasing 1p shell occupation are related to the microscopic structure of the nuclear ground state. Particular attention is given to the partial (γ, N/sub i/) disintegration channels. Complex-particle emission and isospin mixing in the nuclear states are discussed for a few cases. An attempt is made to bring some systematics also in the evidence on excited-state giant resonances through the 1p shell region. The photonuclear GDR is compared with other giant multipole excitations, mostly for the example of the 14 C nucleus. (author)

  15. Study of the giant multipole resonances, especially the isoscalar giant E2 resonance in 208Pb by inelastic electron scattering with medium and high energy resolution

    International Nuclear Information System (INIS)

    Kuehner, E.G.F.

    1982-01-01

    In the nucleus 208 Pb giant multipole resonances were looked for by inelastic electron scattering up to excitation energies of Esub(x) = 35 MeV. Twelve spectra were taken up at incident energies of Esub(o) = 45-65 MeV under scattering angles from upsilon = 93 0 to 165 0 . The cross sections extracted from this were analyzed by means of DWBA calculations using RPA amplitudes from a model with separable residual interaction. Basing on this analysis for the first time it could be shown that the maximum in the electron scattering cross section at Esub(x) approx.= 14 MeV can be consistently described as a superposition of the Jsup(π) = 1 - , ΔT = 1 with a Jsup(π) = 0 + , ΔT = 0 giant resonance. Furthermore the spectra under backward scattering angles indicate the existence of a magnetic excitation at Esub(x) approx.= 15 MeV which is interpreted as Jsup(π) = 3 + giant resonance. Besides under forwards angles a further weak excitation appears at Esub(x) approx.= 14.6 MeV which is very well compatible with Jsup(π) = 2 + . At Esub(x) = 17.5 MeV a Jsup(π) = 3 - resonance was found which recently is also observed in (α,α') scattering experiments and therefore gets a ΔT = 0 assignment. A further resonance at Esub(x) approx.= 21 MeV has also Jsup(π) = 3 - character but has partly to be assigned to a Jsup(π) = 1 - , ΔT = 0 excitation. At Esub(x) = 23.8 MeV a Jsup(π) = 2 + excitation was found which gels because of model predictions a ΔT = 1 assignment. (orig./HSI) [de

  16. Study of the giant multipole resonances especially of the isoscalar giant E2 resonance in 208Pb by medium and high energy resolution inelastic electron scattering

    International Nuclear Information System (INIS)

    Kuehner, G.

    1982-01-01

    In the nucleus 208 Pb giant multipole resonances up to excitation energies of Esub(x) = 35 MeV were looked for by medium resolution inelastic electron scattering. Twelve spectra were taken up at incident energies of E 0 = 45-65 MeV under scattering angles from upsilon = 93 0 to 165 0 . The cross sections extracted from this were analyzed by means of DWBA calculations using RPA amplitudes from a model with separable residual interaction. On the base of this analysis for the first time it could be shown that the maximum in the electron scattering cross section at Esub(x) approx.= 14 MeV can be consistently described as superposition of the Jsup(π) = 1 - , ΔT = 1 with a Jsup(π) = 0 + , ΔT = 0 giant resonance. Furthermore the spectra under backward scattering angles indicate the existence of a magnetic excitation at Esub(x) approx.= 15 MeV which is interpreted as Jsup(π) = 3 + giant resonance. Besides under forward angles a further weak excitation at Esub(x) approx.= 14.6 MeV appears which is very well compatible with Jsup(π) = 2 + . At Esub(x) = 17.5 MeV a Jsup(π) = 3 - resonance was found which recently is observed also in (α, α') experiments and therefore gets a ΔT = 0 assignment. A further resonance at Esub(x) approx.= 21 MeV has also a Jsup(π) = 3 - character but has to be partly assigned to a Jsup(π) = 1 - , ΔT = 0 excitation. At Esub(x) = 23.8 MeV a Jsup(π) = 2 + excitation was found which gets because of model predictions a ΔT = 1 assignment. (orig./HSI) [de

  17. Electromagnetic transitions between giant resonances within a continuum-RPA approach

    NARCIS (Netherlands)

    Rodin, VA; Dieperink, AEL

    2002-01-01

    A general continuum-RPA approach is developed to describe electromagnetic transitions between giant resonances. Using a diagrammatic representation for the three-point Green's function, an expression for the transition amplitude is derived which allows one to incorporate effects of mixing of single

  18. Direct neutron decay from the giant monopole resonance in 208Pb

    International Nuclear Information System (INIS)

    Bracco, A.; Beene, J.R.; Van Giai, N.; Bortignon, P.F.; Zardi, F.; Broglia, R.A.

    1988-01-01

    Experimental values of partial direct escape widths for the giant monopole resonance (GMR) in 208 Pb are presented and compared with predictions from various RPA models. It is found that different model Hamiltonians that reproduce equally well the energy and strength of the GMR in 208 Pb lead to direct escape width which may differ by a large factor. 1 tab

  19. Coupling effects of giant resonances on the elastic and inelastic scattering of fast neutrons

    International Nuclear Information System (INIS)

    Delaroche, J.P.; Tornow, W.

    1983-01-01

    While the inelastic scattering of high energy hadrons is commonly used for the study of giant resonances in nuclei, it is just recently that one has thought to take into account these states in the analysis of proton scattering at low incident energies (E 0 and S 1 . (Auth.)

  20. The photoionization of atomic Eu in the vicinity of its giant resonance

    International Nuclear Information System (INIS)

    Amusia, M.Ya.

    1989-01-01

    It is demonstrated that the partial photoionization cross sections of outer subshells of atomic Eu in the giant resonance region are determined by the action of the 4d-electron excitations. The cross section for photoionization of the semifilled 4f 7 subshell is also entirely dominated by the interaction with 4d 10 electrons. (orig.)

  1. Collective doorways and statistical doorways: The decay properties of giant multipole resonances

    International Nuclear Information System (INIS)

    Dias, H.; Hussein, M.S.; Adhikari, S.K.

    1985-01-01

    A theoretical framework for the description of the decay of giant multipole resonances is developed. It is shown that the statistical decay of the GMR is not necessarily described by the Hauser-Feschbach theory owing to the existence of a mixing parameter. The contribution of pre-equilibrium emission to the GMR decay is also discussed. (Author) [pt

  2. Direct and statistical gamma decay of the giant quadrupole resonance of 208Pb

    International Nuclear Information System (INIS)

    Dias, H.; Hussein, M.S.; Carlson, B.V.; Merchant, A.C.

    1986-03-01

    The gamma decay of the giant quadrupole resonance of 208 Pb is discussed. The relative contribution of the decay via the compound nucleus is calculated from the statistical theory. It is found that the compound decay is as important as the direct decay. (Author) [pt

  3. Giant magnetic modulation of a planar, hybrid metamolecule resonance

    International Nuclear Information System (INIS)

    Gregory, Simon A; Stenning, Gavin B G; Bowden, Graham J; De Groot, Peter A J; Zheludev, Nikolay I

    2014-01-01

    Coupling magnetic elements to metamaterial structures creates hybrid metamolecules with new opportunities. Here we report on the magnetic control of a metamolecule resonance, by utilizing the interaction between a single split ring resonator (SRR) and a magnetic thin film of permalloy. To suppress eddy current shielding, the permalloy films are patterned into arrays of 30–500 μm diameter discs. Strong hybridized resonances were observed at the anticrossing between the split ring resonance and the ferromagnetic resonance (FMR) of the permalloy. In particular, it is possible to achieve 40 dB modulation of the electric (symmetric) mode of the SRR on sweeping the applied magnetic field through the SRR/FMR anticrossing. The results open the way to the design of planar metamaterials, with potential applications in nonlinear metamaterials, tunable metamaterials and spintronics. (papers)

  4. (e,e'f) coincidence experiments for fission decay of giant resonances in 235,238U

    International Nuclear Information System (INIS)

    Weber, T.; Heil, R.D.; Kneissl, U.; Pecho, W.; Wilke, W.; Emrich, H.J.; Kihm, T.; Knoepfle, K.T.

    1988-01-01

    Extending previous work on 238 U, 235 U(e,e'f) coincidence data were taken at 4 momentum transfers yielding both E1, E2/E0 and E3 form factors and the respective multipole strength distributions in the giant resonance region of 238 U (4 x x /Γ a is obtained as a function of excitation energy for separated multipoles. The giant E2 resonance exhibits an increased symmetric fission contribution compared to E1 and E3 resonances. (orig.)

  5. NATO Advanced Study Institute on Giant Resonances in Atoms, Molecules, and Solids

    CERN Document Server

    Esteva, J; Karnatak, R

    1987-01-01

    Often, a new area of science grows at the confines between recognised subject divisions, drawing upon techniques and intellectual perspectives from a diversity of fields. Such growth can remain unnoticed at first, until a characteristic fami ly of effects, described by appropriate key words, has developed, at which point a distinct subject is born. Such is very much the case with atomic 'giant resonances'. For a start, their name itself was borrowed from the field of nuclear collective resonances. The energy range in which they occur, at the juncture of the extreme UV and the soft X-rays, remains to this day a meeting point of two different experimental techniques: the grating and the crystal spectrometer. The impetus of synchrotron spectroscopy also played a large part in developing novel methods, described by many acronyms, which are used to study 'giant resonances' today. Finally, although we have described them as 'atomic' to differentiate them from their counterparts in Nuclear Physics, their occurrence ...

  6. A microscopic study of giant resonances in nuclei near drip lines

    CERN Document Server

    Sagawa, H; Zhang, X Z

    1999-01-01

    We study giant resonances using the self-consistent Hartree-Fock calculation plus the random phase approximation with Skyrme interactions. Including simultaneously both the isoscalar and the isovector correlation the RPA response function is calculated in the coordinate space so as to take properly into account the continuum effect. Giant monopole states are discussed in relation with the nuclear compression modulus of the nuclear matter K sub n sub m. The core polarization charges are also discussed in comparison with recent empirical data in sup 1 sup 0 sup 0 Sn region.

  7. Isoscalar giant resonances for nuclei with mass between 56 and 60

    International Nuclear Information System (INIS)

    Lui, Y.-W.; Youngblood, D.H.; Clark, H.L.; Tokimoto, Y.; John, B.

    2006-01-01

    The giant resonance region from 10 MeV x 56 Fe, 58 Ni, and 60 Ni has been studied with inelastic scattering of 240 MeV α particles at small angles, including 0 deg. Most of the expected isoscalar E0 and E2 strength has been identified below E x =40 MeV. Between 56 and 72% of the isoscalar E1 strength has been located in these nuclei. The mass dependence of the giant monopole energy between A=40 and 90 is compared to relativistic and nonrelativistic calculations for interactions with compressibility of nuclear matter K NM ∼211-225 MeV

  8. Self-organised aggregation of a pair of particles with different resonant frequencies and electric dipole moments of transitions, controlled by an external quasi-resonant field

    Energy Technology Data Exchange (ETDEWEB)

    Slabko, V V; Tsipotan, A S; Aleksandrovsky, A S [Institute of Engineering Physics and Radio Electronics, Siberian Federal University, Krasnoyarsk (Russian Federation)

    2013-05-31

    The influence of the oscillation phases of the dipole moments induced in metal nanoparticles and quantum dots by an external laser field on their interaction energy is considered. It is shown that a difference in resonant frequencies leads to the formation of additional minima and maxima, which are absent in the spectral dependence of the interaction energy of identical particles at similar orientations of the pair of particles with respect to the plane of polarisation of radiation. These features are due to the fact that the oscillation phase difference of the induced dipole moments of particles reaches values close to {pi}. (interaction of laser radiation with matter. laser plasma)

  9. Statistical decay of dipole-excited states of Zr isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Gayer, Udo; Zweidinger, Markus; Beck, Tobias; Mertes, Laura; Pai, Haridas; Pietralla, Norbert; Ries, Philipp; Romig, Christopher; Werner, Volker [IKP, TU Darmstadt (Germany); Cooper, Nathan [University of Richmond, Richmond (United States); Isaak, Johann [EMMI, GSI, Darmstadt (Germany); FIAS, Frankfurt (Germany); Loeher, Bastian; Savran, Deniz [GSI, Darmstadt (Germany); Scheck, Marcus [School of Engineering, UWS, Paisley (United Kingdom); SUPA, Glasgow (United Kingdom); Tornow, Werner [Duke University, Durham (United States)

    2016-07-01

    Decay properties of electric dipole excitations below the neutron separation threshold of {sup 92,94,96}Zr have been determined in several (γ,γ') and (vector γ,γ') experiments at the Darmstadt High Intensity Photon Setup and the High-Intensity Gamma-Ray Source in Durham, USA. The model of statistical decay is used to guide an interpretation of this low-lying dipole strength which is frequently discussed to arise from the low-energy tail of the giant dipole resonance and potentially an additional resonance structure often referred to as the pygmy dipole resonance. The availability of three complete data sets in the Zr isotopic chain allowed for a precise test of these extrapolations to low energies using different models for the level density and the photon strength function. In the talk, data and calculations are presented, and the suitability of photon scattering data for this kind of analysis is discussed.

  10. Angular correlation experiments for the study of giant multipole resonances and currents of the second kind in atomic nuclei

    International Nuclear Information System (INIS)

    1986-03-01

    The project dealt with angular correlation experiments for the study of giant multipole resonances and currents of the second kind in atomic nuclei. Both partial projects were worked in the period of the report. (orig.) [de

  11. Multipole giant resonances of 12C nucleus electro excitation in intermediate coupling model

    International Nuclear Information System (INIS)

    Goncharova, N.G.; Zhivopistsev, F.A.

    1977-01-01

    Multipole giant resonances in 12 C electroexcitation are considered using the shell model with coupling. Cross sections are calculated for the states of 1 - , 2 - , 3 - , 4 - , at T=1. The distributions of the transverse form factor at transferred momenta equal to q approximately 0.75, 1.04, 1.22 and 1.56 Fm -1 and the longitudinal form factor for q = 0.75, 1.04, 1.56 Fm -1 are presented. For the excitation energies in the range from 18 to 28 MeV positive-parity states have a small contribution in the cross section. The distribution of the total form factor in the excitation energies is given. It is concluded that the multipole giant resonances of anomalous parity levels calculated within the interatomic-coupling shell model show a satisfactorily close agreement with the behavior of experimental form factors in the excitation energy range from 18 to 28 MeV

  12. Decay of giant resonances states in radiative pion capture by 1p shell nuclei

    International Nuclear Information System (INIS)

    Dogotar, G.E.

    1978-01-01

    The decay of the giant resonance states excited in tthe radiative pion capture on the 9 Be, 11 B, 13 C and 14 N nuclei is considered in the shell model with intermediate coupling. It is shown that the excited states in the daughter nuclei (A-1, Z-1) are mainly populated by intermediate states with spin by two units larger than the spin of the target nuclei. Selected coincidence experiments are proposed

  13. Nuclear giant resonances in coordinate space. A semiclassical density functional approach

    International Nuclear Information System (INIS)

    Gleissl, P.; Brack, M.; Meyer, J.; Quentin, P.

    1987-01-01

    We discuss the semiclassical description of nuclear giant resonances (GR) using a realistic Skyrme force (SkM*) and complete ETF density functionals. We present monopole (0 + ) eigenmodes of isoscalar (I=0) and isovector (I=1) type, which are in good agreement with experiment, and the corresponding m 1 and m 3 sum rules. We also present the temperature dependence of some typical GR energies (0 + , I=0,1; 1 - , I=1; 2 + , I=0) in 208 Pb

  14. First measurement of isoscalar giant resonances in a stored-beam experiment

    Directory of Open Access Journals (Sweden)

    J.C. Zamora

    2016-12-01

    Full Text Available A new technique developed for measuring nuclear reactions at low momentum transfer with stored beams in inverse kinematics was successfully used to study isoscalar giant resonances. The experiment was carried out at the experimental heavy-ion storage ring (ESR at the GSI facility using a stored 58Ni beam at 100 MeV/u and an internal helium gas-jet target. In these measurements, inelastically scattered α-recoils at very forward center-of-mass angles (θcm≤1.5° were detected with a dedicated setup, including ultra-high vacuum compatible detectors. Experimental results indicate a dominant contribution of the isoscalar giant monopole resonance at this very forward angular range. It was found that the monopole contribution exhausts 79−11+12% of the energy-weighted sum rule (EWSR, which agrees with measurements performed in normal kinematics. This opens up the opportunity to investigate the giant resonances in a large domain of unstable and exotic nuclei in the near future. It is a fundamental milestone towards new nuclear reaction studies with stored ion beams.

  15. Decay of the isoscalar giant monopole resonance in 208Pb and 238U

    International Nuclear Information System (INIS)

    Woude, A. van der

    1985-01-01

    In this paper, the neutron decay of the giant monopole resonance (GMR) of 208 Pb and the alpha decay of the GMR of 238 U is studied. The GMR is excited by inelastic alpha-scattering at small angles (0-3deg) using 120 MeV alpha particles. The interference of other processes like the knock-out process with the particle decay of these resonances is considered. Coincidence neutron and alpha spectra are presented, as well as E2/E0 strength distributions. (Auth.)

  16. Molecular near-field antenna effect in resonance hyper-Raman scattering: Intermolecular vibronic intensity borrowing of solvent from solute through dipole-dipole and dipole-quadrupole interactions

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Rintaro; Hamaguchi, Hiro-o, E-mail: hhama@nctu.edu.tw [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan (China)

    2014-05-28

    We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-β-carotene (β-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute β-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of β-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of β-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of the observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of β-carotene with the vibrations of a proximate solvent molecule through solute–solvent dipole–dipole and dipole–quadrupole interactions. It is shown that the infrared active modes arise from the dipole–dipole interaction, whereas Raman active modes from the dipole–quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10 Å.

  17. Spin-flip isovector giant resonances from the 90Zr (n,p) 90Y reaction at 200 MeV

    International Nuclear Information System (INIS)

    Raywood, K.J.; Spicer, B.M.

    1989-01-01

    Doubly differential cross sections of the reaction 90 Zr(n,p) 90 Y have been measured at 200 MeV for excitations up to 38 MeV in the residual nucleus. An overall resolution of 1.3 MeV was achieved. The spectra show qualitative agreement in shape and magnitude with recent RPA calculations; however all of the calculations underestimate the high excitation region of the spectra. A multipole decomposition of the data has been performed using differential cross sections calculated in the DWIA. An estimate of the Gamow-Teller strength in the reaction is given. The isovector spin-flip dipole giant resonance has been identified and there is also an indication of isovector monopole strength. 39 refs., 16 figs., 1 tab

  18. Giant resonance phenomena in the electron impact ionization of heavy atoms and ions

    International Nuclear Information System (INIS)

    Younger, S.M.

    1986-01-01

    Heavy atoms and ions offer an interesting opportunity to study atomic physics in a region where the atomic structure is dominated by the interelectronic interactions. One illustration of this is the profound term dependence of atomic orbitals for certain configurations of heavy atoms and ions. The appearance of giant scattering resonances in the cross sections for ionization of heavy atoms by electron impact is a manifestation of resonance behavior. Such resonant structures arise from the double well nature of the scattering potential and have recently been identified in the cross sections for the electron impact ionization of several xenon-like ions. The results of calculations showing effects for a variety of other ions are summarized. 7 refs., 4 figs

  19. Decay of the giant quadrupoles resonance and higher excitation states in 40Ca

    International Nuclear Information System (INIS)

    Alamanos, N.; Fernandez, B.; Gillibert, A.

    1991-01-01

    Light charged particles have been measured in coincidence with inelastically scattered fragments from the 40 Ca + 40 Ca reaction at 50 MeV/N. Such a measurement allows to unravel the different reaction mechanisms contributing to the inelastic spectrum: pick-up break-up reactions, knock out and inelastic excitations. The giant quadrupole resonance in 40 Ca is shown to present a 30% non statistical decay branch. A prominent structure at 34 MeV is attributed to target excitation, the decay of this structure is studied

  20. Internal pair decay of giant resonances- signature from ISGMR in hot and heavy nucleus?

    International Nuclear Information System (INIS)

    Banerjee, S.R.

    1996-01-01

    The experimental observation of isoscalar giant monopole resonance built on highly excited nuclear states is still eluding the experimental nuclear physicists although a lot of effort has been put into it. Two very highly sophisticated specific detector systems had been constructed for this study and intense experimental activities were indulged in. Stony Brook pair detector array is being augmented currently to cover about 60% solid angle. There will be another spate of experimental activities and new results will be coming in, but presently there is no experimental observation of ISGMR in hot nucleus

  1. Study of the giant Gamow-Teller resonance in nuclear beta-decay

    International Nuclear Information System (INIS)

    Dicklage, R.D. von; Hansen, P.G.

    1984-01-01

    A strong effort has been devoted to the development of new target-ion-source systems at ISOLDE which would give higher yields of proton-rich nuclei. The first break-trough has been obtained for the element argon where one recently was able to produce about three orders of magnitude higher yields than in the first experiments. This makes it possible to perform experiments, involving β-delayed protons and gamma-rays, which may give information about the giant Gamow-Teller resonance. This paper gives a report on the status of these experiments

  2. Correlated ground state and E2 giant resonance built on it

    International Nuclear Information System (INIS)

    Tohyama, Mitsuru

    1995-01-01

    Taking 16 O as an example of realistic nuclei, we demonstrate that a correlated ground state can be obtained as a long time solution of a time-dependent density-matrix formalism (TDDM) when the residual interaction is adiabatically treated. We also study in TDDM the E2 giant resonance of 16 O built on the correlated ground state and compare it with that built on the Hartree-Fock ground state. It is found that a spurious mixing of low frequency components seen in the latter is eliminated by using the correlated ground state. (author)

  3. Chaos-driven decay of nuclear giant resonances: Quantum route to self-organization

    International Nuclear Information System (INIS)

    Drozdz, S.; Nishizaki, S.; Wambach, J.

    1994-01-01

    The influence of background states with increasing level of complexity on the strength distribution of the isoscalar and isovector giant quadrupole resonance in 40 Ca is studied. It is found that the background characteristics, typical for chaotic systems, strongly affect the fluctuation properties of the strength distribution. In particular, the small components of the wave function obey a scaling law analogous to self-organized systems at the critical state. This appears to be consistent with the Porter-Thomas distribution of the transition strength

  4. Impact-parameter dependence of giant resonance excitations in relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Gruenschloss, A.; Boretzky, K.; Aumann, T.

    1999-09-01

    Angular distributions of Xe fragments produced in peripheral collisions of a 136 Xe beam (700 MeV/nucleon) with 208 Pb and nat Sn targets were measured. Equivalent sharp-cutoff minimum impact parameters were derived on the basis of a semi-classical description for the electromagnetic excitation of one- and two-phonon giant resonances. The results are compared with current standard parametrizations of minimum impact parameters and with the soft-spheres model using realistic mass density distributions for projectile and targets. (orig.)

  5. Quantum chaos in nuclear single-particle motion and damping of giant resonances

    International Nuclear Information System (INIS)

    Pal, Santanu; Mukhopadhyay, Tapan

    1995-01-01

    The spectral statistics of single particle motion in deformed cavities with axial symmetry are presented. The single particle motion in the cavities considered are non-integrable and the systematics of the fluctuation measures of the spectra reveal a transition from regular to chaotic regime in the corresponding classical systems. Quantitative estimate of the degree of chaos enables us to introduce a correction factor to the one-body wall formula for the damping widths of isoscalar giant resonances. The damping widths calculated with this correction factor give much better agreement with experimental values than earlier calculations of one-body damping widths. (author). 21 refs., 5 figs

  6. A particle-hole-rotator coupling model for the giant resonance of carbon-12

    International Nuclear Information System (INIS)

    McDougall, A.; Spicer, B.M.

    1975-01-01

    A collective correlations calculation has been made for the giant resonance of 12 C. The low-lying states are treated as members of two rotational bands, and higher energy low-lying states are included in the coupling procedure in an attempt to examine the connection of these states with structure in the 30-35 MeV region, and to examine a proposed rotational band of states built on the 7.65 MeV (0 + ) level. The calculation fails to transfer strength to the extent expected. (author)

  7. Fine structure of the giant M1 resonance in 90Zr.

    Science.gov (United States)

    Rusev, G; Tsoneva, N; Dönau, F; Frauendorf, S; Schwengner, R; Tonchev, A P; Adekola, A S; Hammond, S L; Kelley, J H; Kwan, E; Lenske, H; Tornow, W; Wagner, A

    2013-01-11

    The M1 excitations in the nuclide 90Zr have been studied in a photon-scattering experiment with monoenergetic and linearly polarized beams from 7 to 11 MeV. More than 40 J(π)=1+ states have been identified from observed ground-state transitions, revealing the fine structure of the giant M1 resonance with a centroid energy of 9 MeV and a sum strength of 4.17(56) μ(N)(2). The result for the total M1 strength and its fragmentation are discussed in the framework of the three-phonon quasiparticle-phonon model.

  8. High-Resolution Measurement of the {sup 4}He({gamma},n) Reaction in the Giant Resonance Region

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Bjoern

    2003-03-01

    A comprehensive near-threshold {sup 4}He(gamma,n) absolute cross section measurement has been performed at the high-resolution tagged-photon facility MAX-lab located in Lund, Sweden. The 20 < Eg < 45 MeV tagged photons (covering the Giant Dipole Resonance energy region) were directed towards a liquid {sup 4}He target, and knocked-out neutrons were detected in a pair of 60 cm x 60 cm vetoed NE213A liquid scintillator arrays. The intense and varying charge-neutral experimental backgrounds were carefully quantified and removed from the data using a precision fitting procedure. Eight average laboratory angles (30, 45, 60, 75, 90, 105, 120, and 135 deg) were investigated for eight photon energy bins (25, 27, 29, 31, 35, 36, 39, and 41 MeV), resulting in 64 differential cross sections. These angular distributions were integrated to produce total cross sections as a function of photon energy. The resulting cross sections peak at 1.9 mb at a photon energy of 27 MeV, and fall off to a near-constant value of 1.1 mb by 36 MeV. Further, they are in excellent agreement with those measured by Sims et al. using tagged photons in the Quasi-Deuteron energy region. Overall, the results favor modern theoretical models which are based upon a charge-symmetric nucleon-nucleon force, in marked contrast to the recommendations made by Calarco et al. in 1983 based on the sparse {sup 4}He(gamma,n) data available at the time.

  9. Excitation of the giant resonance in the radiative pion capture on lp shell nuclei

    International Nuclear Information System (INIS)

    Dogotar', G.E.

    1978-01-01

    The spin-dipole transitions in the (π - ,γ) reaction on 6 Li, 7 Li, 9 Be, 13 C and 14 N are calculated in the framework of shell model and are compared with experiment. The discussion includes the gross structure and the quantum numbers of the resonance, relative branchings, prominent partial transitions and total yields. General findings is that the calculated (π - ,γ) yield distributions describe the data well in those cases where also the photonuclear data are well reproduced, although the amplitudes of the elementary processes are different. In the case considered, the best agreement is obtained for A=9 and 14. The configurational splitting of the resonances is clearly seen in the A=6 and 7 cases, to somewhat less extent also for A=9. For heavier nuclei the contribution from hole excitation is small and is spread out. For A=7 and 11 the calculated main peaks are at too low intrinsic excitation energies as compared with histograms

  10. Magnetic resonance imaging aspects of giant-cell tumours of bone

    International Nuclear Information System (INIS)

    Pereira, Helcio Mendoncça; Marchiori, Edson; Severo, Alessandro

    2014-01-01

    This study aimed to describe the magnetic resonance imaging (MRI) features of giant-cell tumours of bone. We analysed the clinical and MRI features of patients diagnosed with giant-cell tumours of bone confirmed by histopathology at our institution between 2010 and 2012. The peak incidence was between the second and third decades of life. There was no gender predominance. The most frequent locations were the knee and wrist. Pain and swelling were the prevailing symptoms. Fifty-one per cent of the patients were found to have associated secondary aneurysmal bone cysts on histopathology. On MRI, lesions demonstrated signal intensity equal to that of skeletal muscle on T1-weighted images and low signal intensity on T2-weighted images in 90% of cases. In gadolinium-enhanced T1-weighted images, 76.6% of cases demonstrated heterogeneous enhancement. We observed cystic components involving more than 50% of the lesion in 17 cases (56.6%). There was extra-osseous involvement in 13 cases (43.3%). MRI offers a valuable diagnostic tool for giant-cell tumours of bone. Contrast-enhanced MRI can distinguish between cystic and solid components of the tumour. MRI is also the imaging modality of choice for evaluation of soft-tissue involvement, offering a complete preoperative diagnosis.

  11. 1s2p resonant inelastic X-ray scattering combined dipole and quadrupole analysis method

    DEFF Research Database (Denmark)

    Bagger, Alexander; Haarman, Ties; Molina, Anna Puig

    2017-01-01

    , it is shown that only in the case of quadrupole excitations being present is additional information gained by RIXS compared with XAS. Combining this knowledge with methods to calculate the dipole contribution in XAS measurements gives scientists the opportunity to plan more effective experiments....

  12. Giant cell tumor of the tendon sheath of the hand - magnetic resonance image and orthopaedic treatment

    International Nuclear Information System (INIS)

    Kirova, G.; Monovska, T.; Jablanski, V.; Alexieva, K.; Velev, M.

    2009-01-01

    Giant cell tumour of the tendon sheath (GCT-TS), also known as localized nodular tenosynovitis, is a benign neoplasm that occurs dominantly on the digits. These tumours most commonly occur in patients aged 30-50 years and are associated with degenerative joint disease. GCT-TS usually arises from the synovium of tendon sheets, affecting interfalangeal joints of the hand, feet, ankle and knees. Magnetic Resonance Imaging is able to depict characteristic signal intensities and can accurately assess the tumor size and degree of extent around the phalanx. We present a case of a 36 years-old male patient with GCT-TS in the flexor tendon of his left second finger, diagnosed with Magnetic Resonance imaging. The mass was excised widely with preservation of the flexor tendon without recurrence. (authors)

  13. Neutron components of isoscalar giant quadrupole resonance states in 58,60,62,64Ni

    International Nuclear Information System (INIS)

    Antalik, R.

    1989-01-01

    The neutron-proton matrix element ratios (η) for isoscalar giant quadrupole resonance states of even Ni isotopes are investigated within the framework of the shell model quasiparticle random-phase approximation. The dependence of η ratios on radial neutron and proton ground state density distribution differences (Δ np ) is found to be about 1.0-1.5 Δ np . The theoretical η ratios are 14-23% lower than the hydrodynamical limit. The agreement between theoretical and experimental η ratios is observed for 58 Ni and 60 Ni isotopes. The η ratios for 62 Ni and 64 Ni suggested by the resonance π ± inelastic scattering cannot be interpreted even including the radial variations of the neutron fields. 18 refs.; 3 tabs

  14. Inelastic electron scattering, fine structure of M1 giant resonances and Gamow-Teller states

    International Nuclear Information System (INIS)

    Richter, A.

    1983-01-01

    Recent progress in obtaining detailed fine structure distributions of magnetic giant resonances in nuclei using high resolution inelastic electron scattering at low energy is discussed. Specific examples chosen are the medium heavy nuclei 40 42 44 48 Ca in which M1 excitations are due to neutron spin-flip transitions and the N=28 isotones 50 Ti, 52 Cr and 54 Fe where in addition also proton excitations contribute to the measured M1 strength. It is found that the M1 strength is very fragmented and considerably quenched in comparison to predictions of shell model calculations in a model space that includes up to 2p-2h excitations. Finally, the old problem of M1 strength in 208 Pb is revisited and the results of a form factor measurement of a recently discovered low lying Jsup(π)=1 + state by nuclear resonance fluorescence are presented. (Auth.)

  15. Experimental Verification of Isotropic Radiation from a Coherent Dipole Source via Electric-Field-Driven LC Resonator Metamaterials

    Science.gov (United States)

    Tichit, Paul-Henri; Burokur, Shah Nawaz; Qiu, Cheng-Wei; de Lustrac, André

    2013-09-01

    It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator’s gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present.

  16. Giant quadrupole resonance in 24Mg, 27Al, and 28Si

    International Nuclear Information System (INIS)

    Youngblood, D.H.; Rozsa, C.M.; Moss, J.M.; Brown, D.R.; Bronson, J.D.

    1977-01-01

    The giant-resonance region of 24 Mg, 27 Al, and 28 Si was studied by inelastic scattering of 126-MeV α particles. In contrast to results at 96 MeV, considerable clustering of E2 strength was observed for 27 Al at E/sub x/ approx. 20.1 MeV with GAMMA approx. 7.6 MeV exhausting about 35% of the E2 energy weighted sum rule. E2 strength was also located in 24 Mg in two clusters of states at E-bar/sub x/ approx. 18.2, 24.4 MeV; however, contributions from other multipoles cannot be neglected. In 28 Si a multipeaked group was observed at E/sub x/ approx. 19.4 MeV with GAMMA approx. 4 MeV but no L assignment was made. The energy dependence of the cross section for the giant quadrupole resonance was found to be consistent with distorted-wave Born approximation predictions

  17. Investigation of High-Efficiency Wireless Power Transfer Criteria of Resonantly-Coupled Loops and Dipoles through Analysis of the Figure of Merit

    Directory of Open Access Journals (Sweden)

    Charles Moorey

    2015-10-01

    Full Text Available The efficiency of a Wireless Power Transfer (WPT system is greatly dependent on both the geometry and operating frequency of the transmitting and receiving structures. By using Coupled Mode Theory (CMT, the figure of merit is calculated for resonantly-coupled loop and dipole systems. An in-depth analysis of the figure of merit is performed with respect to the key geometric parameters of the loops and dipoles, along with the resonant frequency, in order to identify the key relationships leading to high-efficiency WPT. For systems consisting of two identical single-turn loops, it is shown that the choice of both the loop radius and resonant frequency are essential in achieving high-efficiency WPT. For the dipole geometries studied, it is shown that the choice of length is largely irrelevant and that as a result of their capacitive nature, low-MHz frequency dipoles are able to produce significantly higher figures of merit than those of the loops considered. The results of the figure of merit analysis are used to propose and subsequently compare two mid-range loop and dipole WPT systems of equal size and operating frequency, where it is shown that the dipole system is able to achieve higher efficiencies than the loop system of the distance range examined.

  18. Study of the Pygmy Dipole Resonance in 124Sn by means of the (α,α'γ) reaction

    International Nuclear Information System (INIS)

    Endres, J.; Zilges, A.; Pietralla, N.; Savran, D.; Sonnabend, K.; Harakeh, M. N.; Stoica, V.; Woertche, H.; Butler, P.; Herzberg, R. D.; Scheck, M.; Kruecken, R.; Popescu, L.; Harissopulos, S.; Lagoyannis, A.

    2009-01-01

    In recent years α-γ coincidence experiments at 136 MeV incident energy on 48 Ca, 140 Ce, 138 Ba and 124 Sn were performed at the KVI in Groningen to study the isospin character of electric dipole excitations below the particle threshold, frequently called Pygmy Dipole Resonance (PDR). An array of HPGe γ-detectors has been used in coincidence with the Big-Bite Spectrometer (BBS) and a resolution of about 10 keV in the γ-ray energy has been achieved. The results show that the excitation patterns of the PDR in the (α,α') reaction seem to differ significantly from results obtained in Nuclear Resonance Fluorescence (NRF)(γ,γ') measurements. The PDR, which until now has been assigned to one excitation mode, splits up into two parts: One that is excited in (α,α'γ) and (γ,γ') reactions (denoting a dominant isoscalar character), and one that is only excited in (γ,γ')(denoting a dominant isovector character). This indicates that two different excitation mechanisms produce these low-lying E1 excitations [1], The preliminary results of the latest measurements on the N = 82 nucleus 138 Ba and the Z = 50 nucleus 124 Sn show that this break up into two parts is a common feature of the PDR in semi-magic nuclei.

  19. Total and differential cross sections for pion production via coherent isobar and giant resonance formation in heavy-ion collisions

    International Nuclear Information System (INIS)

    Deutchman, P.A.; Norbury, J.W.; Townsend, L.W.

    1985-01-01

    A quantal many-body formalism is presented that investigates pion production through the coherent formation of a nucleonic isobar in the projectile and its subsequent decay to various pion charge states along with concomitant excitation of the target to a coherent spin-isospin giant resonance via a peripheral collision of relativistic heavy ions. Total cross sections as a function of the incident energy per nucleon and Lorentz-invariant differential cross sections as a function of pion energy and angle are calculated. It is shown that the pion angular distributions, in coincidence with the target giant resonance excitations, might provide a well-defined signature for these coherent processes

  20. Collective dipole motion in highly excited (272)Hs (Z=108) nuclei

    NARCIS (Netherlands)

    Tveter, TS; Gaardhoje, JJ; Maj, A; Ramsay, T; Atac, A; Bacelar, J; Bracco, A; Buda, A; Camera, F; Herskind, B; Korten, W; Krolas, W; Menthe, A; Million, B; Nifenecker, H; Pignanelli, M; Pinston, JA; vanderPloeg, H; Schussler, F; Sletten, G

    1996-01-01

    The heavy nucleus (272)(108)Hs (Z = 108) and its evaporation daughters were produced using the reaction Th-232(Ar-40, gamma xn) with beam energies 10.5 and 15.0 MeV/A. The giant dipole resonance gamma radiation from the hot composite system prior to fission has been isolated using a differential

  1. Electric quadrupole giant resonance in the photofission of sup(238)U IFUSP-P--140

    International Nuclear Information System (INIS)

    Bhandari, B.S.; Arruda Neto, J.D.T.; Herdade, S.B.; Nascimento, I.C.

    1978-02-01

    The 238 U nucleus was studied measuring the electrofission yield and angular distributions of fission fragments, in the energy range of 5.5 to 28.3 MeV, using a new method of analysis. An E2 isoscalar giant resonance was found in the photofission cross section of 238 U. This resonance exhausts (71 + -7)% of the EWSR and is located at 9.9 + -0.2 MeV with a width of 6.8 + -0.4 MeV. The position of this resonance is in reasonable agreement with the Bohr and Mottelson prediction (58.Asup( - 1/3MeV). The width of 6.8 + -0.4 MeV is compatible with a possible triple splitting of the resonance. From the angular distributions of photofission fragments and yield measurements of multipoles other than E1, evidence of an M1 mixture in the energy region 6-7 MeV was found

  2. Giant thermo-optical relaxation oscillations in millimeter-size whispering gallery mode disk resonators.

    Science.gov (United States)

    Diallo, Souleymane; Lin, Guoping; Chembo, Yanne K

    2015-08-15

    In this Letter, we show that giant thermo-optical oscillations can be triggered in millimeter (mm)-size whispering gallery mode (WGM) disk resonators when they are pumped by a resonant continuous-wave laser. Our resonator is an ultrahigh-Q barium fluoride cavity that features a positive thermo-optic coefficient and a negative thermo-elastic coefficient. We demonstrate for the first time, to our knowledge, that the complex interplay between these two thermic coefficients and the intrinsic Kerr nonlinearity yields very sharp slow-fast relaxation oscillations with a slow timescale that can be exceptionally large, typically of the order of 1 s. We use a time-domain model to gain understanding into this instability, and we find that both the experimental and theoretical results are in excellent agreement. The understanding of these thermal effects is an essential requirement for every WGM-related application and our study demonstrates that even in the case of mm-size resonators, such effects can still be accurately analyzed using nonlinear time-domain models.

  3. Cardiac Sarcoidosis or Giant Cell Myocarditis? On Treatment Improvement of Fulminant Myocarditis as Demonstrated by Cardiovascular Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Hari Bogabathina

    2012-01-01

    Full Text Available Giant cell myocarditis, but not cardiac sarcoidosis, is known to cause fulminant myocarditis resulting in severe heart failure. However, giant cell myocarditis and cardiac sarcoidosis are pathologically similar, and attempts at pathological differentiation between the two remain difficult. We are presenting a case of fulminant myocarditis that has pathological features suggestive of cardiac sarcoidosis, but clinically mimicking giant cell myocarditis. This patient was treated with cyclosporine and prednisone and recovered well. This case we believe challenges our current understanding of these intertwined conditions. By obtaining a sense of severity of cardiac involvement via delayed hyperenhancement of cardiac magnetic resonance imaging, we were more inclined to treat this patient as giant cell myocarditis with cyclosporine. This resulted in excellent improvement of patient’s cardiac function as shown by delayed hyperenhancement images, early perfusion images, and SSFP videos.

  4. Concerning the generation of geomagnetic giant pulsations by drift-bounce resonance ring current instabilities

    Directory of Open Access Journals (Sweden)

    K.-H. Glassmeier

    Full Text Available Giant pulsations are nearly monochromatic ULF-pulsations of the Earth's magnetic field with periods of about 100 s and amplitudes of up to 40 nT. For one such event ground-magnetic observations as well as simultaneous GEOS-2 magnetic and electric field data and proton flux measurements made in the geostationary orbit have been analysed. The observations of the electromagnetic field indicate the excitation of an odd-mode type fundamental field line oscillation. A clear correlation between variations of the proton flux in the energy range 30-90 keV with the giant pulsation event observed at the ground is found. Furthermore, the proton phase space density exhibits a bump-on-the-tail signature at about 60 keV. Assuming a drift-bounce resonance instability as a possible generation mechanism, the azimuthal wave number of the pulsation wave field may be determined using a generalized resonance condition. The value determined in this way, 
    m
    = - 21 ± 4, is in accord with the value m = - 27 ± 6 determined from ground-magnetic measurements. A more detailed examination of the observed ring current plasma distribution function f shows that odd-mode type eigenoscillations are expected for the case ∂f / ∂W > 0, much as observed. This result is different from previous theoretical studies as we not only consider local gradients of the distribution function in real space, but also in velocity space. It is therefore concluded that the observed giant pulsation is the result of a drift-bounce resonance instability of the ring current plasma coupling to an odd-mode fundamental standing wave. The generation of the bump-on-the-tail distribution causing ∂f / ∂W > 0 can be explained due to velocity dispersion of protons injected into the ring current. Both this velocity dispersion and the necessary substorm activity causing the injection of protons into the nightside magnetosphere are observed

  5. Concerning the generation of geomagnetic giant pulsations by drift-bounce resonance ring current instabilities

    Directory of Open Access Journals (Sweden)

    K.-H. Glassmeier

    1999-03-01

    Full Text Available Giant pulsations are nearly monochromatic ULF-pulsations of the Earth's magnetic field with periods of about 100 s and amplitudes of up to 40 nT. For one such event ground-magnetic observations as well as simultaneous GEOS-2 magnetic and electric field data and proton flux measurements made in the geostationary orbit have been analysed. The observations of the electromagnetic field indicate the excitation of an odd-mode type fundamental field line oscillation. A clear correlation between variations of the proton flux in the energy range 30-90 keV with the giant pulsation event observed at the ground is found. Furthermore, the proton phase space density exhibits a bump-on-the-tail signature at about 60 keV. Assuming a drift-bounce resonance instability as a possible generation mechanism, the azimuthal wave number of the pulsation wave field may be determined using a generalized resonance condition. The value determined in this way,  m = - 21 ± 4, is in accord with the value m = - 27 ± 6 determined from ground-magnetic measurements. A more detailed examination of the observed ring current plasma distribution function f shows that odd-mode type eigenoscillations are expected for the case ∂f / ∂W > 0, much as observed. This result is different from previous theoretical studies as we not only consider local gradients of the distribution function in real space, but also in velocity space. It is therefore concluded that the observed giant pulsation is the result of a drift-bounce resonance instability of the ring current plasma coupling to an odd-mode fundamental standing wave. The generation of the bump-on-the-tail distribution causing ∂f / ∂W > 0 can be explained due to velocity dispersion of protons injected into the ring current. Both this velocity dispersion and the necessary substorm activity causing the injection of protons into the nightside magnetosphere are observed.Key words. Magnetospheric physics (energetic particles , trapped

  6. Concentration dependence of the wings of a dipole-broadened magnetic resonance line in magnetically diluted lattices

    Energy Technology Data Exchange (ETDEWEB)

    Zobov, V. E., E-mail: rsa@iph.krasn.ru [Russian Academy of Sciences, Kirenskii Institute of Physics, Siberian Branch (Russian Federation); Kucherov, M. M. [Siberian Federal University, Institute of Space and Information Technologies (Russian Federation)

    2017-01-15

    The singularities of the time autocorrelation functions (ACFs) of magnetically diluted spin systems with dipole–dipole interaction (DDI), which determine the high-frequency asymptotics of autocorrelation functions and the wings of a magnetic resonance line, are studied. Using the self-consistent fluctuating local field approximation, nonlinear equations are derived for autocorrelation functions averaged over the independent random arrangement of spins (magnetic atoms) in a diamagnetic lattice with different spin concentrations. The equations take into account the specificity of the dipole–dipole interaction. First, due to its axial symmetry in a strong static magnetic field, the autocorrelation functions of longitudinal and transverse spin components are described by different equations. Second, the long-range type of the dipole–dipole interaction is taken into account by separating contributions into the local field from distant and near spins. The recurrent equations are obtained for the expansion coefficients of autocorrelation functions in power series in time. From them, the numerical value of the coordinate of the nearest singularity of the autocorrelation function is found on the imaginary time axis, which is equal to the radius of convergence of these expansions. It is shown that in the strong dilution case, the logarithmic concentration dependence of the coordinate of the singularity is observed, which is caused by the presence of a cluster of near spins whose fraction is small but contribution to the modulation frequency is large. As an example a silicon crystal with different {sup 29}Si concentrations in magnetic fields directed along three crystallographic axes is considered.

  7. Comment on '(p,n) and (n,p) reactions as probes of isovector giant monopole resonances'

    International Nuclear Information System (INIS)

    Bauhoff, W.

    1984-01-01

    The importance of medium corrections in the excitation of the isovector giant monopole resonance by nucleons is investigated. A large reduction of the cross-section, compared to calculations with free t-matrices, is found at projectile energies around 100 MeV. This will make observation of the isovector monopole at these energies even more difficult than estimated by Auerbach et al

  8. The structure of the Gamow-Teller giant resonance and consequences for beta-delayed neutron spectra and element synthesis

    International Nuclear Information System (INIS)

    Klapdor, H.V.

    1976-01-01

    Recent results in β-delayed neutron emission are interpreted by structure of the Gamow-Teller giant resonance not included in the 'gross-theory' of β-decay. Inclusion of this structure of the β-decay function is important for calculations of β-decay production rates for heavy nuclides by astrophysical processes and thermonuclear explosions. (Auth.)

  9. Interacting sp-boson model with isospin: an unified description of giant multipole resonances and other collective motions

    International Nuclear Information System (INIS)

    Chen, C.H.-T.

    1980-10-01

    A unified description of the following classes of nuclear collective states in terms of an interacting sp-boson model is proposed: (i) Low-lying collective states in the light nuclei, both odd-odd and even-even; (ii) Giant multipole resonances (GMR), and (iii) pairing collective motions. (Author) [pt

  10. Multiple coil pulsed magnetic resonance method for measuring cold SSC dipole magnet field quality

    International Nuclear Information System (INIS)

    Clark, W.G.; Moore, J.M.; Wong, W.H.

    1990-01-01

    The operating principles and system architecture for a method to measure the magnetic field multipole expansion coefficients are described in the context of the needs of SSC dipole magnets. The operation of an 8-coil prototype system is discussed. Several of the most important technological issues that influence the design are identified and the basis of their resolution is explained. The new features of a 32-coil system presently under construction are described, along with estimates of its requirements for measurement time and data storage capacity

  11. Sequential changes of magnetic resonance images of intracavernous giant aneurysm following carotid ligation

    International Nuclear Information System (INIS)

    Kinjo, Toshihiko; Mukawa, Jiro; Takara, Eiichi; Mekaru, Susumu; Ishikawa, Yasunari

    1986-01-01

    A case of intracavernous giant aneurysm treated by combined carotid ligation and extracranial-intracranial vein-graft bypass is reported with special reference to the sequential changes of Magnetic Resonance Images (MRI). A 29-year-old female was admitted to our clinic with complaint of diplopia. She had no neurological deficit except for left abducens palsy. Left carotid angiogram revealed an intracavernous giant aneurysm, and vertebral angiogram revealed a fenestration at right and an aneurysm-like buldging at left vertebral artery. Gradual carotid occlusion after extracranial-intracranial bypass via grafted saphnous vein was successfully performed without any neurological complications. Sequential changes of MRI were as follows: The aneurysm was shown by absent intensity both in spin echo (SE) and inversion recovery (IR) methods before the treatment. It became isointensity in SE and two-tone intensity, iso at the center and high at the margin, in IR 15 days after, and, furtheremore, became slight high intensity in SE but decreased in two-tone intensity, low at the center and high at the margin, in IR 37 days after complete carotid occlusion. Coronal view was usefull to understand anatomical relationship. In conclusion, MRI, especially coronal IR method is of more diagnostic value than X-ray CT to follow the thrombosis of intracavernous aneurysm. (author)

  12. A Resonant Scanning Dipole-Antenna Probe for Enhanced Nanoscale Imaging

    NARCIS (Netherlands)

    Neumann, L.; van 't Oever, Jan Joannes Frederik; van Hulst, N.F.

    2013-01-01

    We present a scanning antenna probe that provides 35 nm optical hotspots with a 16-fold excitation enhancement. A resonant optical antenna, tuned to operation in the visible, is carved into the aluminum-coated scanning probe. The antenna resonances, field localization, excitation, and polarization

  13. Giant angular resonance and the structure of the lowest-lying nuclear states

    International Nuclear Information System (INIS)

    Mikhajlov, I.N.; Usmanov, P.N.; Yuldashbaeva, Eh.Kh.

    1987-01-01

    The analysis is given of the Hamiltonian of the two-rotor model, which is based on the assumption that the giant angular resonance exists, i.e. that it is possible to rotate the neutron component of a deformed nucleus as a whole with respect to the proton component. The realization of the projections on the intrinsic axes of the angular momentum operators is found, the Hamiltonian matrix is determined in the basis convenient for the case of strong neutron-proton coupling. The spectrum of the two-rotor model is determined taking into account the nondiagonal matrix elements in the lowest order of the perturbation theory. The g factors and the probabilities of the M1 transitions are discussed

  14. Temperature dependence and fragmentation of the particle-hole giant resonances

    International Nuclear Information System (INIS)

    Seva, E.C.; Sofia, H.M.

    1997-01-01

    We evaluate the spreading width of the giant multipole resonances at finite temperature using the discontinuity in the second derivative of the Green close-quote s function of the vibrational boson, in the Matsubara close-quote s framework. Our method allows us to identify the processes that contribute to the spreading width in terms of the Feynman diagrammatic expansion of the full boson propagator. We have applied the calculation of the spreading width to the 208 Pb and the 90 Zr obtaining an increment of the spreading width with the temperature. We have not reached any saturation of the spreading width increment, at least up to the temperature of our calculation. copyright 1997 The American Physical Society

  15. Fine structure of the isoscalar giant quadrupole resonance in 40Ca due to Landau damping?

    International Nuclear Information System (INIS)

    Usman, I.; Buthelezi, Z.; Carter, J.; Cooper, G.R.J.; Fearick, R.W.; Foertsch, S.V.; Fujita, H.; Fujita, Y.; Kalmykov, Y.; Neumann-Cosel, P. von; Neveling, R.; Papakonstantinou, P.; Richter, A.; Roth, R.; Shevchenko, A.; Sideras-Haddad, E.; Smit, F.D.

    2011-01-01

    The fragmentation of the Isoscalar Giant Quadrupole Resonance (ISGQR) in 40 Ca has been investigated in high energy-resolution experiments using proton inelastic scattering at E p =200 MeV. Fine structure is observed in the region of the ISGQR and its characteristic energy scales are extracted from the experimental data by means of a wavelet analysis. The experimental scales are well described by Random Phase Approximation (RPA) and second-RPA calculations with an effective interaction derived from a realistic nucleon-nucleon interaction by the Unitary Correlation Operator Method (UCOM). In these results characteristic scales are already present at the mean-field level pointing to their origination in Landau damping, in contrast to the findings in heavier nuclei and also to SRPA calculations for 40 Ca based on phenomenological effective interactions, where fine structure is explained by the coupling to two-particle-two-hole (2p-2h) states.

  16. CO2-laser-microwave double-resonance spectroscopy of D2CO: precise measurement of the dipole moment in the ground state

    International Nuclear Information System (INIS)

    Tanaka, K.; Nakahara, Y.; Yamaguchi, M.; Tanaka, T.

    1987-01-01

    The method of CO 2 -laser-microwave double resonance (LMDR) with an intense electric field was used to measure Stark shifts of ground-state microwave transitions of D 2 CO. Thirty LMDR signals originating from 15 K-doublet transitions were observed, associated with the infrared transitions of the ν 4 and ν 6 bands. Least-squares analysis of the observed LMDR signals yields precise values of the coefficients in the dipole-moment expansion, μ 0 +μ/sub J/ J(J+1)+μ/sub K/ K 2 : μ 0 , 2.347 134(8) D; μ/sub j/, -4.76(10) x 10 -6 D; μ/sub K/, -28.7(18) x 10 -6 D; where one-standard-deviation uncertainties are given in parentheses. The infrared--infrared double-resonance signals of PH 3 , which were calibrated against the OCS dipole moment, were used for the electric-field calibration, allowing us to determine the dipole moment with a precision of 10 parts in 10 6 (ppm). However, the absolute accuracy of the dipole moment obtained is 50 ppm, as limited by the uncertainty of the OCS dipole moment. The effective dipole moment for the 1/sub 1.0/ reverse arrow 1/sub 1.1/ transition measured in the present study agrees well with the effective dipole moment for the 1/sub 1.0/ rotational level from a molecular-beam electric resonance experiment. The μ/sub J/ and μ/sub K/ coefficients calculated from Watson's θ/sub γ//sup α//sup β/ constants agree well with the experimental values

  17. Nuclear fluid dynamics with long-mean-free-path dissipation: Multipole vibrations and isoscalar giant resonance widths

    International Nuclear Information System (INIS)

    Hasse, R.W.; Ghosh, G.

    1982-01-01

    The long-mean-free-path nuclear fluid dynamics is extended to include damping. First the damping stress is derived from the solution of the Boltzmann equation for a breathing spherical container filled with a Fermi gas. Then the corresponding damping force is incorporated into Euler equations of motion and energies and widths of low lying collective resonances are computed as eigenfrequencies of a vibrating nucleus under surface tension and Coulomb potential as well as the high lying isoscalar giant resonances as eigenfrequencies of an elastic nucleus. Maximum damping is obtained if the particle frequency approximately resonates with the wall frequency. Theoretical results are compared with experimental data and future improvements are indicated

  18. Transmission of waves near the lower oblique resonance using dipoles in the ionosphere

    Czech Academy of Sciences Publication Activity Database

    Chugunov, Yu. V.; Mareev, E. A.; Fiala, Vladimír; James, H. G.

    2003-01-01

    Roč. 38, č. 2 (2003), s. 5-1-5-10 ISSN 0048-6604 R&D Projects: GA MŠk ME 356 Institutional research plan: CEZ:AV0Z3042911 Keywords : plasma * resonance cone * effective length Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.832, year: 2003

  19. Studies on the resonant properties in the asymmetric dipole-array terahertz metamaterials

    Science.gov (United States)

    Chen, Wei; Zhou, Qingli; Li, Chenyu; Shi, Lan; Liu, Changxiang; Zhang, Cunlin

    2018-01-01

    Artificial metamaterials with appropriate design can exhibit unique electromagnetic phenomena which do not exist in natural materials. Some studies have shown that the method of breaking the geometric symmetry is capable to modify the electromagnetic response, such as the metamaterial induced transparency in the Fano resonators. In this work, by using the finite-difference time-domain method, we firstly simulate the process that terahertz wave interacts with double-bar structures, in which one bar length is fixed at 36 μm and the other bar length is set to be 12, 24, 36, 48, and 56 μm, respectively. The incident terahertz polarization is along the bar direction. Simulated results show when the variable bar length is less than 36 μm, there is only one obvious resonant dip in transmission spectrum. Meanwhile, with the decreased bar length, this dip frequency presents a slight blueshift. Additionally, by tuning the spacing vertical to bar direction between these two bars, it still exhibits one dip. This result indicates the short bar less than 36 μm does not play important role and the coupling between vertical bars is weak. However, when the variable bar length is larger than 36 μm there are two obvious Fano-shaped resonant dips. With the increased bar length, the low-frequency dip shows a remarkable redshift, while the high-frequency one is almost unchanged. By further tuning the bar spacing vertical to the bar direction, two dips always exist. This phenomenon implies that the coupling between horizontal bars is dominated in this process. Moreover, the metamaterial induced transparency window is found between two resonant dips. The appearance of the resonances is attributed to the excitation of trapped mode. Our obtained results indicate that such metamaterials with very simple configuration could also provide the potential application in the field of terahertz slow-light devices, amplitude and phase modulators.

  20. Creation of polarized ultracold neutrons and observation of Ramsey resonance for electric dipole moment measurement

    Energy Technology Data Exchange (ETDEWEB)

    Matsuta, K., E-mail: matsuta@vg.phys.sci.osaka-u.ac.jp [Osaka University, Department of Physics (Japan); Masuda, Y. [High Energy Accelerator Research Organization (KEK) (Japan); Hatanaka, K. [Osaka University, RCNP (Japan); Jeong, S. C.; Kawasaki, S. [High Energy Accelerator Research Organization (KEK) (Japan); Matsumiya, R. [Osaka University, RCNP (Japan); Mihara, M. [Osaka University, Department of Physics (Japan); Watanabe, Y. [High Energy Accelerator Research Organization (KEK) (Japan); Nishimura, D. [Tokyo University of Science, Department of Physics (Japan); Morita, Y. [Osaka University, Department of Physics (Japan); Asahi, K. [Tokyo Institute of Technology (Japan); Adachi, T. [High Energy Accelerator Research Organization (KEK) (Japan); Martin, J. [University of Winnipeg, Department of Physics (Canada); Konaka, A.; Miller, A. [TRIUMF (Canada); Bidinosti, C.; Dawson, T. [University of Winnipeg, Department of Physics (Canada); Lee, L.; Davis, C.; Ramsay, D. [TRIUMF (Canada); and others

    2013-05-15

    Polarized UCNs have been created by selecting only one spin state passing through a magnetized Fe foil. Typical degree of polarization was about 90 %. The polarization relaxation time in the prototype Ramsey cell was T{sub 1} =1100{sup +800}{sub -400} s. Clear Ramsey resonance spectra have been observed for two precession time settings, t{sub c} = 100 ms and 30 s. The transverse relaxation time T{sub 2} was about 50 s.

  1. Finite temperature effects on monopole and dipole excitations

    International Nuclear Information System (INIS)

    Niu, Y F; Paar, N; Vretenar, D; Meng, J

    2011-01-01

    The relativistic random phase approximation based on effective Lagrangian with density dependent meson-nucleon couplings has been extended to finite temperature and employed in studies of multipole excitations within the temperature range T = 1 - 2 MeV. The model calculations showed that isoscalar giant monopole and isovector giant dipole resonances are only slightly modified with temperature, but additional transition strength appears at low energies because of thermal unblocking of single-particle orbitals close to the Fermi level. The analysis of low-lying states shows that isoscalar monopole response in 132 Sn results from single particle transitions, while the isovector dipole strength for 60 Ni, located around 10 MeV, is composed of several single particle transitions, accumulating a small degree of collectivity.

  2. Dipole polarizability and neutron skin in {sup 68}Ni

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Dominic [GSI Darmstadt (Germany); Univ. Mainz (Germany); NSCL, MSU (United States); Aumann, Thomas [TU Darmstadt (Germany); Boretzky, Konstanze [GSI Darmstadt (Germany); Collaboration: R3B-Collaboration

    2014-07-01

    The symmetry energy term E{sub sym} of the nuclear equation-of-state describes fundamental phenomena both in nuclear physics and in astrophysics. The electric dipole (E1) response of nuclei as a function of the isospin asymmetry is driven by E{sub sym} and in particular by its density dependence. Studies of the Pygmy Dipole Resonance (PDR) in exotic nuclei have been used to constrain E{sub sym} or the neutron skin thickness ΔR{sub n,p}. The electric dipole polarizability α{sub D}, being very sensitive to the low-lying E1 strength, is correlated to ΔR{sub n,p} in a robust and only moderately less model-dependent manner [PRC 81, 051303 (2010)]. Recently, for the stable nucleus, 208Pb the neutron skin thickness was extracted from the measured αD. Here, a first experimental determination of α{sub D} in an unstable nucleus and the derivation of its ΔR{sub n,p} will be reported. Coulomb excitation in inverse kinematics at the R3B-LAND setup at GSI allows for the investigation of the dipole strength distribution in the neutron-rich {sup 68}Ni covering the pygmy (PDR) and giant dipole resonance (GDR). The E1 strength distribution in the neutron-rich {sup 68}Ni covering the pygmy (PDR) and giant dipole resonance (GDR) s investigated using the R3B-LAND setup at GSI. From the E1 strength distribution in {sup 68}Ni measured using the R3B-LAND setup at GSI, the resonance parameters for the observed PDR at 9.55(17) MeV and the giant dipole resonance at 17.1(2) MeV are determined. In combination with results from Wieland et al. [PRL 102, 092502 (2009)] an unexpectedly large direct photon-decay branching ratio of 7(2) is observed for the PDR. The measured α{sub D} of 3.40(23) fm{sup 3} is compared to relativistic RPA calculations yielding ΔR{sub n,p} of 0.17(2) fm for {sup 68}Ni.

  3. Giant resonance spectroscopy of 40Ca with the (e,e'x) reaction (I): Experiments and overview of results

    International Nuclear Information System (INIS)

    Diesener, H.; Helm, U.; Neumann-Cosel, P. von; Richter, A.; Schrieder, G.; Stascheck, A.; Stiller, A.; Carter, J.

    2001-01-01

    The 40 Ca(e,e'x; x=p,α) reaction has been measured in the giant resonance excitation region for E x ≅8-26 MeV. The present article is the first out of three describing the experiments and giving an overview of the results. Data were taken at four momentum transfers in the range q=0.26-0.66 fm -1 . Angular correlations for decay to the ground state and low-lying states of 39 K and 36 Ar could be extracted as a function of excitation energy in 40 Ca. Excitation energy spectra integrated over the particle emission angle were generated for the various resolved decay channels. Comparisons of the giant resonance cross-section distributions with results using other electromagnetic or hadronic probes have been made and good agreement is found in most cases

  4. Time-dependent Hartree-Fock calculation of the escape width of the giant monopole resonance in 16O

    International Nuclear Information System (INIS)

    Pacheco, J.M.; Maglione, E.; Broglia, R.A.

    1988-01-01

    The damping of the giant monopole resonance in 16 O is calculated within the framework of the time-dependent Hartree-Fock approximation. The strength function contains two peaks, centered at around 25 and 33 MeV, with escape widths of ∼11 and ∼2 MeV, associated with the 1p(0p) -1 and 1s(0s) -1 configurations, respectively

  5. Peripheral collisions of heavy ions induced by 40Ar at intermediate energies: giant resonance high energy structures and projectile fragmentation

    International Nuclear Information System (INIS)

    Blumenfeld, Y.

    1987-09-01

    The results obtained in similar studies at low incident energies are first of all reviewed. The time of flight spectrometer built for the experiments is then described. A study of the properties of the projectile-like fragments shows numerous deviations from the relativistic energy fragmentation model. Evidence for a strong surface transfer reaction component is given and the persistence of mean field effects at intermediate energies is stressed. A calculation of the contribution of the transfer evaporation mechanism to the inelastic spectra shows that this mechanism is responible for the major part of the background measured at high excitation energy and can in some cases induce narrow structures in the spectra. The inelastic spectra shows a strong excitation of the giant quadrupole resonance. In the region between 20 and 80 MeV excitation energy narrow structures are present for all the studied systems. Statistical and Fourier analysises allow to quantify the probabilities of existence, the widths and the excitation energies of these structures. A transfer evaporation hypothesis cannot consistently reproduce all the observed structures. The excitation energies of the structures can be well described by phenomenological laws where the energies are proportional to the -1/3 power of the target mass. Complete calculations of the excitation probabilities of giant resonances and multiphonon states are performed within a model where the nuclear excitation are calculated microscopically in the Random Phase Approximation. It is shown that a possible interpretation of the structures is the excitation of multiphonon states built with 2 + giant resonances [fr

  6. TERRESTRIAL PLANET FORMATION DURING THE MIGRATION AND RESONANCE CROSSINGS OF THE GIANT PLANETS

    International Nuclear Information System (INIS)

    Lykawka, Patryk Sofia; Ito, Takashi

    2013-01-01

    The newly formed giant planets may have migrated and crossed a number of mutual mean motion resonances (MMRs) when smaller objects (embryos) were accreting to form the terrestrial planets in the planetesimal disk. We investigated the effects of the planetesimal-driven migration of Jupiter and Saturn, and the influence of their mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by performing N-body simulations. These simulations considered distinct timescales of MMR crossing and planet migration. In total, 68 high-resolution simulation runs using 2000 disk planetesimals were performed, which was a significant improvement on previously published results. Even when the effects of the 1:2 MMR crossing and planet migration were included in the system, Venus and Earth analogs (considering both orbits and masses) successfully formed in several runs. In addition, we found that the orbits of planetesimals beyond a ∼ 1.5-2 AU were dynamically depleted by the strengthened sweeping secular resonances associated with Jupiter's and Saturn's more eccentric orbits (relative to the present day) during planet migration. However, this depletion did not prevent the formation of massive Mars analogs (planets with more than 1.5 times Mars's mass). Although late MMR crossings (at t > 30 Myr) could remove such planets, Mars-like small mass planets survived on overly excited orbits (high e and/or i), or were completely lost in these systems. We conclude that the orbital migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely to provide suitable orbital conditions for the formation of solar system terrestrial planets. This suggests that to explain Mars's small mass and the absence of other planets between Mars and Jupiter, the outer asteroid belt must have suffered a severe depletion due to interactions with Jupiter/Saturn, or by an alternative mechanism (e.g., rogue super-Earths)

  7. On the role of anti-bound states in the RPA description of the giant monopole resonance

    International Nuclear Information System (INIS)

    Vertse, T.; Bang, J.

    1989-01-01

    The limit of the applicability of the resonant Random Phase Approximation (RPA) method is tested by calculating escape widths in the giant monopole resonance of 16 O and comparing them to the results of a time dependent Hartree-Fock calculation. Though the widths of the narrow s-wave component agree reasonably well, the broad p-wave component shows large disagreement, which cannot be cured by complementing the basis with anti-bound states in the RPA calculation. (author) 18 refs.; 3 tabs

  8. Excitation of giant monopole resonance in {sup 208}Pb and {sup 116}Sn using inelastic deuteron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Patel, D.; Garg, U. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Itoh, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Akimune, H. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Berg, G.P.A. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Fujiwara, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Harakeh, M.N. [Kernfysisch Versneller Instituut, University of Groningen, 9747 AA Groningen (Netherlands); GANIL, CEA/DSM-CNRS/IN2P3, 14076 Caen (France); Iwamoto, C. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Kawabata, T. [Division of Physics and Astronomy, Kyoto University, Kyoto 606-8502 (Japan); Kawase, K. [Japan Atomic Energy Agency, Kyoto 619-0215 (Japan); Matta, J.T. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Murakami, T. [Division of Physics and Astronomy, Kyoto University, Kyoto 606-8502 (Japan); Okamoto, A. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Sako, T. [Japan Atomic Energy Agency, Kyoto 619-0215 (Japan); Schlax, K.W. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Takahashi, F. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); White, M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Yosoi, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan)

    2014-07-30

    The excitation of the isoscalar giant monopole resonance (ISGMR) in {sup 208}Pb and {sup 116}Sn has been investigated using small-angle (including 0°) inelastic scattering of 100 MeV/u deuteron and multipole-decomposition analysis (MDA). The extracted strength distributions agree well with those from inelastic scattering of 100 MeV/u α particles. These measurements establish deuteron inelastic scattering at E{sub d}∼100 MeV/u as a suitable probe for extraction of the ISGMR strength with MDA, making feasible the investigation of this resonance in radioactive isotopes in inverse kinematics.

  9. Study of the pygmy dipole resonance in {sup 94}Mo using the (α,α{sup ′}γ) coincidence technique

    Energy Technology Data Exchange (ETDEWEB)

    Derya, V., E-mail: derya@ikp.uni-koeln.de [Institut für Kernphysik, Universität zu Köln, Zülpicher Straße 77, 50937 Köln (Germany); Endres, J.; Elvers, M. [Institut für Kernphysik, Universität zu Köln, Zülpicher Straße 77, 50937 Köln (Germany); Harakeh, M.N. [Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); Pietralla, N.; Romig, C. [Institut für Kernphysik, TU Darmstadt, Schlossgartenstraße 9, 64289 Darmstadt (Germany); Savran, D. [ExtreMe Matter Institute EMMI and Research Division, GSI, Planckstraße 1, 64291 Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main (Germany); Scheck, M.; Siebenhühner, F. [Institut für Kernphysik, TU Darmstadt, Schlossgartenstraße 9, 64289 Darmstadt (Germany); Stoica, V.I. [Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); Department of Sociology/ICS, Rijksuniversiteit Groningen, Grote Rozenstraat 31, 9712 TG Groningen (Netherlands); Wörtche, H.J. [Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); and others

    2013-05-15

    The (α,α{sup ′}γ) reaction at E{sub α}=136 MeV was used to study the electric dipole response in the open-shell vibrational nucleus {sup 94}Mo below the neutron-separation threshold. The coincidence experiment has been performed at the Kernfysisch Versneller Instituut in Groningen, The Netherlands, exploiting the Big-Bite Spectrometer and an array of large volume High-Purity Germanium (HPGe) detectors. Due to the excellent energy resolution and high selectivity to transitions stemming from the pygmy dipole resonance, singles α-scattering cross sections could be determined for individual electric dipole excitations between 4 and 8 MeV. For three of the excited low-lying J{sup π}=1{sup −} states in {sup 94}Mo a γ-decay branch into the J{sup π}=2{sub 1}{sup +} state could be observed. The experiment extends the systematic studies of the pygmy dipole resonance by real-photon scattering (γ,γ{sup ′}) experiments and (α,α{sup ′}γ) experiments. Recently, a (γ,γ{sup ′}) experiment on {sup 94}Mo was performed at the Darmstadt High-Intensity Photon Setup at the S-DALINAC in Darmstadt, Germany, permitting the comparison of B(E1)↑ strength distribution and α-scattering cross sections.

  10. Suppression of nonlinear frequency-sweeping of resonant interchange modes in a magnetic dipole with applied radio frequency fields

    International Nuclear Information System (INIS)

    Maslovsky, D.; Levitt, B.; Mauel, M. E.

    2003-01-01

    Interchange instabilities excited by energetic electrons trapped by a magnetic dipole nonlinearly saturate and exhibit complex, coherent spectral characteristics and frequency sweeping [H. P. Warren and M. E. Mauel, Phys. Plasmas 2, 4185 (1995)]. When monochromatic radio frequency (rf) fields are applied in the range of 100-1000 MHz, the saturation behavior of the interchange instability changes dramatically. For applied fields of sufficient intensity and pulse-length, coherent interchange fluctuations are suppressed and frequency sweeping is eliminated. When rf fields are switched off, coherent frequency sweeping reappears. Since low frequency interchange instabilities preserve the electron's first and second adiabatic invariants, these observations can be interpreted as resulting from nonlinear resonant wave-particle interactions described within a particle phase-space, (ψ,φ), comprised of the third adiabatic invariant and the azimuthal angle. Self-consistent numerical simulation is used to study (1) the nonlinear development of the instability, (2) the radial mode structure of the interchange instability, and (3) the suppression of frequency sweeping. When the applied rf heating is modeled as an 'rf collisionality', the simulation reproduces frequency sweeping suppression and suggests an explanation for the observations that is consistent with Berk and co-workers [H. L. Berk et al., Phys. Plasmas 6, 3102 (1999)

  11. The electric dipole response of neutron rich tin isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Horvat, Andrea; Aumann, Thomas; Rossi, Dominic; Schindler, Fabia [Institut fuer Kernphysik, TU Darmstadt (Germany); Boretzky, Konstanze [GSI Helmholzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Johansen, Jacob [Aarhus University (Denmark); Schrock, Philipp [The University of Tokyo (Japan); Collaboration: R3B-Collaboration

    2016-07-01

    Studies of the dipole response in medium heavy and heavy neutron rich nuclei reveal valuable information about the isospin dependence of the nuclear equation of state. Therefore an experimental campaign investigating both the electric dipole response via Coulomb excitation and neutron removal along the tin isotope chain ({sup 124-134}Sn) has been carried out at the R3B (Reactions with Relativistic Radioactive Beams) setup at GSI (Helmholtzzentrum fuer Schwerionenforschung) for which the analysis is ongoing. The E1 response was induced via relativistic Coulomb scattering by a lead target in inverse kinematics, and calls for a kinematically complete determination of all reaction products in order to reconstruct the excitation energy by means of the invariant mass method. The goal is to obtain the Coulomb excitation cross section up to the adiabatic cut-off energy, covering the giant dipole resonance (GDR) range.

  12. Fine structure of the isoscalar giant quadrupole resonance from high-resolution inelastic proton scattering experiments

    International Nuclear Information System (INIS)

    Shevchenko, A.

    2005-02-01

    In the present work the phenomenon of fine structure in the region of the isoscalar giant quadrupole resonance in a number of heavy and medium-heavy nuclei is systematically investigated for the first time. High energy-resolution inelastic proton scattering experiments were carried out in September-October 2001 and in October 2003 at the iThemba LABS cyclotron facility in South Africa with an incident proton energy of 200 MeV. The obtained data with the energy resolution of triangle E 58 Ni, 89 Y, 90 Zr, 120 Sn, 142 Nd, 166 Er, 208 Pb), thereby establishing the global character of this phenomenon. Fine structure can be described using characteristic energy scales, appearing as a result of the decay of collective modes towards the compound nucleus through a hierarchy of couplings to complex degrees of freedom. For the extraction of the characteristic energy scales from the spectra an entropy index method and a novel technique based on the wavelet analysis are utilized. The global analysis of available data shows the presence of three groups of scales, according to their values. To the first group belong the scales with the values around and below 100 keV, which were detected in all the nuclei studied. The second group contains intermediate scales in the range of 100 keV to 1 MeV. These scales show large variations depending on the nuclear structure of the nucleus. The largest scales above 1 MeV are classified to the third group, describing the global structure of the resonance (the width). The interpretation of the observed scales is realized via the comparison with microscopic model calculations including the coupling of the initial one-particle-one-hole excitations to more complex configurations. A qualitative agreement of the experimentally observed scales with those obtained from the theoretical predictions supports the suggestion of the origin of fine structure from the coupling to the two-particle-two-hole states. However, quantitatively, large deviations are

  13. Microwave conductivity and spin resonance of Si- nK centers at dislocation dipoles in silicon

    Science.gov (United States)

    Konchits, A. A.; Shanina, B. D.

    1995-11-01

    Non-resonance microwave absorption (NRMA) due to microwave conductivity (MC) of Czochralski-grown silicon crystal has been studied. The temperature dependence of the MC was measured in the temperature range from 1.7 to 40 K in darkness as well as under the interband light. Exponential growth of the MC in a low temperature range is described within the extended one-dimensional Hubbard model for the case of an arbitrary filled band. The activation energy of electron hopping motion in darkness is found to be similar to that in amorphous silicon (0.4 meV), although, under light its value is significantly larger (12 meV). The logarithmic law is revealed for the MC decay. The value of its time constant τ0 at T = 4.2 K changes with the light intensity I from 4 to 57 s, so τ0 is proportional to I-1. The exponential recovery process at T = 4.2 K goes rather slowly, with τ1 in interval from 0.4 to 3.11 min depending on the location of the donor levels in a band gap. It is shown that the linear law connects the dependence of the TD-2 EPR intensity increase and the Si- nK EDSR intensity decrease versus the MC decay under continuous illumination.

  14. Electromagnetic moments and electric dipole transitions in carbon isotopes

    International Nuclear Information System (INIS)

    Suzuki, Toshio; Sagawa, Hiroyuki; Hagino, Kouichi

    2003-01-01

    We carry out shell model calculations to study electromagnetic moments and electric dipole transitions of C isotopes. We point out the configuration dependence of the quadrupole and magnetic moments of the odd C isotopes, which will be useful to find out the deformations and the spin parities of the ground states of these nuclei. We also study the electric dipole states of C isotopes, focusing on the interplay between low energy pigmy strength and giant dipole resonances. As far as the energies of the resonances are concerned, reasonable agreement is obtained with available experimental data for the photoreaction cross sections in 12 C, 13 C, and 14 C, both in the low energy region below (ℎ/2π)ω=14 MeV and in the high energy giant resonance region (14 MeV 15 C is found to exhaust about 12-16 % of the classical Thomas-Reiche-Kuhn sum rule value and 50-80 % of the cluster sum rule value

  15. Electric dipole strength and dipole polarizability in 48Ca within a fully self-consistent second random–phase approximation

    Directory of Open Access Journals (Sweden)

    D. Gambacurta

    2018-02-01

    Full Text Available The second random–phase–approximation model corrected by a subtraction procedure designed to cure double counting, instabilities, and ultraviolet divergences, is employed for the first time to analyze the dipole strength and polarizability in 48Ca. All the terms of the residual interaction are included, leading to a fully self-consistent scheme. Results are illustrated with two Skyrme parametrizations, SGII and SLy4. Those obtained with the SGII interaction are particularly satisfactory. In this case, the low-lying strength below the neutron threshold is well reproduced and the giant dipole resonance is described in a very satisfactory way especially in its spreading and fragmentation. Spreading and fragmentation are produced in a natural way within such a theoretical model by the coupling of 1 particle-1 hole and 2 particle-2 hole configurations. Owing to this feature, we may provide for the electric polarizability as a function of the excitation energy a curve with a similar slope around the centroid energy of the giant resonance compared to the corresponding experimental results. This represents a considerable improvement with respect to previous theoretical predictions obtained with the random–phase approximation or with several ab-initio models. In such cases, the spreading width of the excitation cannot be reproduced and the polarizability as a function of the excitation energy displays a stiff increase around the predicted centroid energy of the giant resonance.

  16. Electric dipole strength and dipole polarizability in 48Ca within a fully self-consistent second random-phase approximation

    Science.gov (United States)

    Gambacurta, D.; Grasso, M.; Vasseur, O.

    2018-02-01

    The second random-phase-approximation model corrected by a subtraction procedure designed to cure double counting, instabilities, and ultraviolet divergences, is employed for the first time to analyze the dipole strength and polarizability in 48Ca. All the terms of the residual interaction are included, leading to a fully self-consistent scheme. Results are illustrated with two Skyrme parametrizations, SGII and SLy4. Those obtained with the SGII interaction are particularly satisfactory. In this case, the low-lying strength below the neutron threshold is well reproduced and the giant dipole resonance is described in a very satisfactory way especially in its spreading and fragmentation. Spreading and fragmentation are produced in a natural way within such a theoretical model by the coupling of 1 particle-1 hole and 2 particle-2 hole configurations. Owing to this feature, we may provide for the electric polarizability as a function of the excitation energy a curve with a similar slope around the centroid energy of the giant resonance compared to the corresponding experimental results. This represents a considerable improvement with respect to previous theoretical predictions obtained with the random-phase approximation or with several ab-initio models. In such cases, the spreading width of the excitation cannot be reproduced and the polarizability as a function of the excitation energy displays a stiff increase around the predicted centroid energy of the giant resonance.

  17. (π±, π±' N) reactions on 12C and 208Pb near the giant resonance region

    International Nuclear Information System (INIS)

    Yoo, Sung Hoon.

    1990-05-01

    Angular distributions for the 12 C(π ± , π ± ' p) and 208 Pb(π ± , π ± ' p or n) reactions near the giant resonance region have been measured at T π = 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 208 Pb, neutron and proton doorway states. In a heavy nucleus such as 208 Pb, neutron and proton doorway states contribute incoherently because the different decay processes do not populate the same final states of the residual nucleus

  18. Photoionization of Xe inside C60: Atom-fullerene hybridization, giant cross-section enhancement, and correlation confinement resonances

    International Nuclear Information System (INIS)

    Madjet, Mohamed E.; Renger, Thomas; Hopper, Dale E.; McCune, Matthew A.; Chakraborty, Himadri S.; Rost, Jan-M.; Manson, Steven T.

    2010-01-01

    A theoretical study of the subshell photoionization of the Xe atom endohedrally confined in C 60 is presented. Powerful hybridization of the Xe 5s state with the bottom edge of C 60 π band is found that induces strong structures in the 5s ionization, causing the cross section to differ significantly from earlier results that omit this hybridization. The hybridization also affects the angular distribution asymmetry parameter of Xe 5p ionization near the Cooper minimum. The 5p cross section, on the other hand, is greatly enhanced by borrowing considerable oscillator strength from the C 60 giant plasmon resonance via the atom-fullerene dynamical interchannel coupling. Beyond the C 60 plasmon energy range the atomic subshell cross sections display confinement-induced oscillations in which, over the large 4d shape resonance region, the dominant 4d oscillations induce their ''clones'' in all degenerate weaker channels known as correlation confinement resonances.

  19. Excitation of giant modes and decay of hot nuclei

    International Nuclear Information System (INIS)

    Chomaz, Ph.

    1992-01-01

    Several phenomena are discussed which can affect the properties of the Giant Dipole Resonance (GDR) built on excited states. The effect of the N over Z ratio is proposed in the entrance channel to test the hypothesis that the saturation of the GDR strength is due to preequilibrium effects. The important role of the compression is discussed both for the calculation of the temperature and for the other parameters of the Hot GDR. (K.A.) 15 refs.; 9 figs

  20. Giant Vertebral Notochordal Rest: Magnetic Resonance and Diffusion Weighted Imaging Findings

    International Nuclear Information System (INIS)

    Oner, Ali Yusuf; Akpek, Sergin; Tali, Turgut; Ucar, Murat

    2009-01-01

    A giant vertebral notochordal rest is a newly described, benign entity that is easily confused with a vertebral chordoma. As microscopic notochordal rests are rarely found in adult autopsies, the finding of a macroscopic vertebral lesion is a new entity with only seven previously presented cases. We report here radiological findings, including diffusion weighted images, of a patient with a giant notochordal remnant confined to the L5 vertebra, with an emphasis on its distinction from a chordoma

  1. ACOL dipoles

    International Nuclear Information System (INIS)

    Vlogaert, J.

    1987-01-01

    This paper describes the general design of ACOL dipoles, including the special injection area dipole. A list of mechanical, electrical and magnetic parameters and results of magnetic measurements are presented. Particular attention is paid to the proximity effects between quadrupoles and dipoles

  2. A SECOND GIANT PLANET IN 3:2 MEAN-MOTION RESONANCE IN THE HD 204313 SYSTEM

    International Nuclear Information System (INIS)

    Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Brugamyer, Erik J.; Barnes, Stuart I.; Caldwell, Caroline; Horner, J.; Wittenmyer, Robert A.; Simon, Attila E.

    2012-01-01

    We present eight years of high-precision radial velocity (RV) data for HD 204313 from the 2.7 m Harlan J. Smith Telescope at McDonald Observatory. The star is known to have a giant planet (Msin i = 3.5 M J ) on a ∼1900 day orbit, and a Neptune-mass planet at 0.2 AU. Using our own data in combination with the published CORALIE RVs of Ségransan et al., we discover an outer Jovian (Msin i = 1.6 M J ) planet with P ∼ 2800 days. Our orbital fit suggests that the planets are in a 3:2 mean motion resonance, which would potentially affect their stability. We perform a detailed stability analysis and verify that the planets must be in resonance.

  3. Using Schumann Resonance Measurements for Constraining the Water Abundance on the Giant Planets - Implications for the Solar System Formation

    Science.gov (United States)

    Simoes, Fernando; Pfaff, Robert; Hamelin, Michel; Klenzing, Jeffrey; Freudenreich, Henry; Beghin, Christian; Berthelier, Jean-Jacques; Bromund, Kenneth; Grard, Rejean; Lebreton, Jean-Pierre; hide

    2012-01-01

    The formation and evolution of the Solar System is closely related to the abundance of volatiles, namely water, ammonia, and methane in the protoplanetary disk. Accurate measurement of volatiles in the Solar System is therefore important to understand not only the nebular hypothesis and origin of life but also planetary cosmogony as a whole. In this work, we propose a new, remote sensing technique to infer the outer planets water content by measuring Tremendously and Extremely Low Frequency (TLF-ELF) electromagnetic wave characteristics (Schumann resonances) excited by lightning in their gaseous envelopes. Schumann resonance detection can be potentially used for constraining the uncertainty of volatiles of the giant planets, mainly Uranus and Neptune, because such TLF-ELF wave signatures are closely related to the electric conductivity profile and water content.

  4. USING SCHUMANN RESONANCE MEASUREMENTS FOR CONSTRAINING THE WATER ABUNDANCE ON THE GIANT PLANETS—IMPLICATIONS FOR THE SOLAR SYSTEM'S FORMATION

    International Nuclear Information System (INIS)

    Simões, Fernando; Pfaff, Robert; Klenzing, Jeffrey; Freudenreich, Henry; Bromund, Kenneth; Martin, Steven; Rowland, Douglas; Hamelin, Michel; Berthelier, Jean-Jacques; Béghin, Christian; Lebreton, Jean-Pierre; Grard, Rejean; Sentman, Davis; Takahashi, Yukihiro; Yair, Yoav

    2012-01-01

    The formation and evolution of the solar system is closely related to the abundance of volatiles, namely water, ammonia, and methane in the protoplanetary disk. Accurate measurement of volatiles in the solar system is therefore important for understanding not only the nebular hypothesis and origin of life but also planetary cosmogony as a whole. In this work, we propose a new remote sensing technique to infer the outer planets' water content by measuring Tremendously and Extremely Low Frequency (TLF-ELF) electromagnetic wave characteristics (Schumann resonances) excited by lightning in their gaseous envelopes. Schumann resonance detection can be potentially used for constraining the uncertainty of volatiles of the giant planets, mainly Uranus and Neptune, because such TLF-ELF wave signatures are closely related to the electric conductivity profile and water content.

  5. Metamaterial Combining Electric- and Magnetic-Dipole-Based Configurations for Unique Dual-Band Signal Enhancement in Ultrahigh-Field Magnetic Resonance Imaging.

    Science.gov (United States)

    Schmidt, Rita; Webb, Andrew

    2017-10-11

    Magnetic resonance imaging and spectroscopy (MRI and MRS) are both widely used techniques in medical diagnostics and research. One of the major thrusts in recent years has been the introduction of ultrahigh-field magnets in order to boost the sensitivity. Several MRI studies have examined further potential improvements in sensitivity using metamaterials, focusing on single frequency applications. However, metamaterials have yet to reach a level that is practical for routine MRI use. In this work, we explore a new metamaterial implementation for MRI, a dual-nuclei resonant structure, which can be used for both proton and heteronuclear magnetic resonance. Our approach combines two configurations, one based on a set of electric dipoles for the low frequency band, and the second based on a set of magnetic dipoles for the high frequency band. We focus on the implementation of a dual-nuclei metamaterial for phosphorus and proton imaging and spectroscopy at an ultrahigh-field strength of 7 T. In vivo scans using this flexible and compact structure show that it locally enhances both the phosphorus and proton transmit and receive sensitivities.

  6. Dipole polarizability of neutron rich nuclei and the symmetry energy

    Energy Technology Data Exchange (ETDEWEB)

    Horvat, Andrea; Johansen, Jacob; Miki, Kenjiro; Schindler, Fabia; Schrock, Philipp [IKP, TU Darmstadt (Germany); Aumann, Thomas [IKP, TU Darmstadt (Germany); GSI, Darmstadt (Germany); Boretzky, Konstanze [GSI, Darmstadt (Germany); Collaboration: R3B-Collaboration

    2015-07-01

    As a part of a systematic investigation of the dipole response of stable up to very neutron rich tin isotopes, nuclear and electromagnetic excitation of {sup 124}Sn-{sup 134}Sn has been investigated at relativistic energies in inverse kinematics induced by carbon and lead targets at the LAND-R3B setup at GSI in Darmstadt. The electric dipole response and the nuclear reaction cross section, total and charge-changing, are obtained from the kinematically complete determination of momenta of all particles on an event by event basis. The dipole polarizability is extracted from the Coulomb excitation interaction channel, in order to make use of relevant correlations of this observable with nuclear matter properties such as the symmetry energy at saturation density (J) and it's slope (L). The systematics of the low-lying ''pygmy'' dipole strength, the giant dipole resonance (GDR) and the neutron skin thickness are determined with respect to increasing isospin asymmetry. This talk also discusses the correlations and sensitivities of these variables and observables obtained within the framework of nuclear energy density functional theory.

  7. Study of quadrupolar transitions by 108.5 MeV 3He inelastic scattering at small angles. Anomalous behaviour of giant quadrupole resonance

    International Nuclear Information System (INIS)

    Bouhelal, O.K.

    1982-07-01

    Giant resonances have been studied through the inelastic scattering of 108.5 MeV 3 He on several nuclei. At the very small angles (theta 0 ), the quadrupole giant resonance experimental cross-section is about twice the value predicted by DWBA calculations based on a collective model. The comparison of the experimental data and the theoretical data calculations confirms the validity of DWBA for the first excited state of low energy and same multipolarity L = 2 at the very small angles. The angular distribution for L = 0 transition of energy close to that of the quadrupole giant resonance reaches its maximum at 0 0 . The presence of an L = 0 component permits to describe the shape of the quadrupole giant resonance angular distribution, but difficulties are encountered when applying the sum rule for the heavy nuclei. Better agreement with the experimental angular distribution at small angles is obtained if a semimicroscopic convolution model of the quadrupole resonance is assumed. For excited states of low energy and multipolarity L not equal to 2, the results from the convolution model are as good as those from the standard collective model. The 2 + state in heavy nuclei is, however, much better described by the collective model [fr

  8. Active coated nano-particle excited by an arbitrarily located electric Hertzian dipoleresonance and transparency effects

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Ziolkowski, Richard W.

    2010-01-01

    The present work investigates the optical properties of active coated spherical nano-particles excited by an arbitrarily located electric Hertzian dipole. The nano-particles are made of specific dielectric and plasmonic materials. The spatial near-field distribution as well as the normalized...

  9. Tailoring surface plasmon resonance and dipole cavity plasmon modes of scattering cross section spectra on the single solid-gold/gold-shell nanorod

    International Nuclear Information System (INIS)

    Chou Chau, Yuan-Fong; Lim, Chee Ming; Kumara, N. T. R. N.; Yoong, Voo Nyuk; Lee, Chuanyo; Huang, Hung Ji; Lin, Chun-Ting; Chiang, Hai-Pang

    2016-01-01

    Tunable surface plasmon resonance (SPR) and dipole cavity plasmon modes of the scattering cross section (SCS) spectra on the single solid-gold/gold-shell nanorod have been numerically investigated by using the finite element method. Various effects, such as the influence of SCS spectra under x- and y-polarizations on the surface of the single solid-gold/gold-shell nanorod, are discussed in detail. With the single gold-shell nanorod, one can independently tune the relative SCS spectrum width by controlling the rod length and rod diameter, and the surface scattering by varying the shell thickness and polarization direction, as well as the dipole peak energy. These behaviors are consistent with the properties of localized SPRs and offer a way to optically control and produce selected emission wavelengths from the single solid-gold/gold-shell nanorod. The electric field and magnetic distributions provide us a qualitative idea of the geometrical properties of the single solid-gold/gold-shell nanorod on plasmon resonance.

  10. Electron paramagnetic resonance line shifts and line shape changes due to heisenberg spin exchange and dipole-dipole interactions of nitroxide free radicals in liquids 8. Further experimental and theoretical efforts to separate the effects of the two interactions.

    Science.gov (United States)

    Peric, Mirna; Bales, Barney L; Peric, Miroslav

    2012-03-22

    The work in part 6 of this series (J. Phys. Chem. A 2009, 113, 4930), addressing the task of separating the effects of Heisenberg spin exchange (HSE) and dipole-dipole interactions (DD) on electron paramagnetic resonance (EPR) spectra of nitroxide spin probes in solution, is extended experimentally and theoretically. Comprehensive measurements of perdeuterated 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (pDT) in squalane, a viscous alkane, paying special attention to lower temperatures and lower concentrations, were carried out in an attempt to focus on DD, the lesser understood of the two interactions. Theoretically, the analysis has been extended to include the recent comprehensive treatment by Salikhov (Appl. Magn. Reson. 2010, 38, 237). In dilute solutions, both interactions (1) introduce a dispersion component, (2) broaden the lines, and (3) shift the lines. DD introduces a dispersion component proportional to the concentration and of opposite sign to that of HSE. Equations relating the EPR spectral parameters to the rate constants due to HSE and DD have been derived. By employing nonlinear least-squares fitting of theoretical spectra to a simple analytical function and the proposed equations, the contributions of the two interactions to items 1-3 may be quantified and compared with the same parameters obtained by fitting experimental spectra. This comparison supports the theory in its broad predictions; however, at low temperatures, the DD contribution to the experimental dispersion amplitude does not increase linearly with concentration. We are unable to deduce whether this discrepancy is due to inadequate analysis of the experimental data or an incomplete theory. A new key aspect of the more comprehensive theory is that there is enough information in the experimental spectra to find items 1-3 due to both interactions; however, in principle, appeal must be made to a model of molecular diffusion to separate the two. The permanent diffusion model is used to

  11. Photon nuclear scattering on lead and bismuth in the region of the giant resonance

    International Nuclear Information System (INIS)

    Tamas, Gabriel.

    1976-01-01

    The results of monochromatic photon nuclear scattering studies on natural lead and bismuth targets are presented. The cross sections for the inelastic scattering leading to the first excited levels of 204 Pb, 206 Pb and 207 Pb are important, in agreement with theoretical predictions. The elastic scattering amplitude is related to the total photon absorption by dispersion relations. It is then possible to determine the spin of resonances excited by the reaction studied. Precise measurements carried out between 14 and 20MeV revealed that the angular distribution cannot be explained by a single dipolar resonance. A quadrupolar resonance at E 2 =14MeV must be introduced [fr

  12. Excitation of giant resonances in 20Ne + 90Zr and 208Pb inelastic scattering at 40 MeV/u1

    International Nuclear Information System (INIS)

    Suomijaervi, T.; Beaumel, D.; Blumenfeld, Y.; Chomaz, P.; Frascaria, N.; Garron, J.P.; Jacmart, J.C.; Roynette, J.C.; Kraus, L.; Link, I.

    1988-01-01

    The giant resonance region in the inelastic spectra from the reactions 20 Ne + 90 Zr and 20 Ne + 208 Pb at 40 MeV/nucleon has been studied with a good energy and angular resolutions. The strength distributions of the different multipolarities contributing to the cross section were obtained by a resonance shape independent analysis. In the case of 208 Pb the GDR strength was found to be strongly shifted towards lower excitation energies which can be explained by the exponentially decreasing Coulomb excitation probability. Furthermore, indications for a high multipolarity component in the resonance structure were found in both reactions

  13. The role fo the Pygmy resonance in the synthesis of heavy elements with radioactive beams

    International Nuclear Information System (INIS)

    Hussein, M.S.

    1990-12-01

    It is suggested that the inclusion of the virtual excitation of the soft giant dipole (pygmy) resonance in the calculation of the cross-section for very neutron-rich radioactive beam-induced fusion reactions may enhance the formation probability of the heavy compound nucleus produced at low excitation energy. (author)

  14. Excitation of the giant quadrupole resonance in /sup 58/Ni with /sup 20/Ne

    CERN Document Server

    Bohlen, H G; Ingold, G; Lettau, H; Ossenbrink, H; von Oertzen, W

    1981-01-01

    The heavy-ion induced excitation of the quadrupole resonance in /sup 58/Ni has been studied with /sup 20/Ne beams of 14.5 and 19.6 MeV/N incident energy. The broad resonance structure is clearly observed; the strength exhausts 44% and 60% of the energy weighted sum rule (EWSR) at the two incident energies, respectively. The background is partly explained by a three-body reaction mechanism, which is based on the one-nucleon pick-up reaction into unbound states followed by one- nucleon emission. The remaining part is interpreted as inelastic excitation of other multipoles. (11 refs).

  15. Operador dipolo-dipolo na base de momento angular: um complemento ao estudo de ressonância magnética nuclear Dipole-dipole operator in angular momentum basis: a complementary study in nuclear magnetic resonance

    Directory of Open Access Journals (Sweden)

    Rita de Cássia de Oliveira Sebastião

    2008-01-01

    Full Text Available The relationship between the magnetic dipole-dipole potential energy function and its quantum analogue is presented in this work. It is assumed the reader is familiar with the classical expression of the dipolar interaction and has basic knowledge of the quantum mechanics of angular momentum. Except for these two points only elementary steps are involved.

  16. The low energy photon tagger NEPTUN: Toward a detailed study of the Pygmy dipole resonance with real photons

    Energy Technology Data Exchange (ETDEWEB)

    Semmler, Diego; Aumann, T.; Bauer, C.; Baumann, M.; Beckstein, M.; Beller, J.; Blecher, A.; Cvejin, N.; Duchene, M.; Hug, F.; Kahlbow, J.; Knoerzer, M.; Kreis, K.; Kremer, C.; Ries, P.; Romig, C.; Scheit, H.; Schnorrenberger, L.; Symochko, D.; Walz, C. [Institut fuer Kernphysik, Darmstadt (Germany); Lefol, R. [University of Saskatchewan, Saskatoon (Canada); Loeher, B. [ExtreMe Matter Institute EMMI and Research Division, Frankfurt (Germany); Institute for Advanced Studies FIAS, Frankfurt (Germany)

    2014-07-01

    The low energy photon tagger NEPTUN at the S-DALINAC delivers a quasi-monoenergetic photon beam between about 4 MeV and 20 MeV with a resolution of approximately 25 keV. Tagged photons provide the possibility to measure the dipole strength of nuclei in the energy range below and above the neutron threshold. The highly efficient LaBr{sub 3} based spectrometer GALATEA will be used to detect not only the direct decays to the ground state, but also cascading decays can be measured with suitable efficiency. We will measure (γ,n)- and (γ,nγ)-reactions with neutron detectors based on plastic scintillators. This talk provides an overview about setup and goals of the NEPTUN experiment as well as the current state of the commissioning phase. Planned optimizations of the setup, based on the results of a test beam time in June 2013, are also presented.

  17. Evaluation of characteristics of some giant multipole resonances within a many-particle approach

    International Nuclear Information System (INIS)

    Steshenko, A.J.

    1994-01-01

    Within a microscopic approach including the many-particle basis of longitudinal-vibration functions (Sp 2 (2,R))-basis) the widths and energies of some gigantic isoscalar monopole and quadrupole resonances in light magic and near-magic nuclei have been calculated. The theoretical results are in agreement with the available experimental data

  18. Prompt High Energy Dipole γ Emission

    International Nuclear Information System (INIS)

    Corsi, A.; Giaz, A; Bracco, A.

    2011-01-01

    The study of the collective properties of a nuclear system is a powerful tool to understand the structure which lies inside the nucleus. A successful technique which has been used in this field is the measurement of the γ-decay of the highly collective Giant Dipole Resonance (GDR). In fact, GDR can be used as a probe for the internal structure of hot nuclei and, in addition, constitutes a clock for the thermalization process. Using the fusion-evaporation reaction, it has been recently possible to study (i) the yield of the high-energy γ-ray emission of the Dynamical Dipole which takes place during the fusion process and (ii) the degree of isospin mixing at high temperature in the decay of 80 Zr. In the first case it is important to stress the fact that the predictions of the theoretical models might differ depending on the type of nuclear equation of state (EOS) and on the N-N in-medium cross-section used in the calculations while, in the second physics case, the data are relative to the heaviest N = Z nucleus which has been possible to populate in the I = 0 channel using fusion-evaporation reaction. Both experiments were performed at the Laboratori Nazionali di Legnaro using the HECTOR-GARFIELD array. The high-energy γ-rays were measured in coincidence with light charged particles and fusion-evaporation residues. (author)

  19. The importance of the giant resonances in hadron and muon induced fission

    International Nuclear Information System (INIS)

    Hartfiel, J.

    1985-01-01

    In the first part of the thesis the fission probability of 238 U by means of the reaction 238 U(α,α'f) is studied at an incident energy of 480 MeV and a scattering angle of 3.4 0 . In the measured spectrum of the inelastically scattered α particles a strong resonance is found in the excitation energy range from 8 to 13 MeV. The center of mass of the resonance lies at 11 MeV. Its width extends to 4.5 MeV. In the second part of the thesis the muon induced fission of 235 U, 238 U, 237 Np, 242 Pu, and 244 Pu is studied. Thereby both fission fragments are detected in coincidence by two surface barrier detectors. By this it is possible for the first time to measure the mass and kinetic energy distribution of the fission fragments. (orig./HSI) [de

  20. Development and test of the e+e- pair spectrometer for the detection of the electromagnetic decay of the E0 giant resonance state

    International Nuclear Information System (INIS)

    Katayama, I.; Fujita, Y.; Fujiwara, M.; Morinobu, S.; Ikegami, H.

    1978-01-01

    A lens type pair spectrometer of electron and positron has been developed and tested in order to detect the electromagnetic decay (pair creation) of the E0 giant resonance state. It was found from the one day machine time test (targets: natural Mo and Pb, beam:α, 70 MeV) that the improvement of the apparatus is necessary for getting a definite information on the yield of high energy electron pairs. (author)

  1. Solid state deuterium nuclear magnetic resonance detection of transmembrane-potential-driven tetraphenylphosphonium redistribution across Giant Unilamellar Vesicle bilayers

    International Nuclear Information System (INIS)

    Franzin, Carla Maria Mirella

    1995-01-01

    It has been demonstrated that deuterium nuclear magnetic resonance ( 2 H NMR) of Giant Unilamellar Vesicles (GUVs) consisting of specifically choline-deuterated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), plus 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) and cholesterol can be used to monitor the transbilayer redistribution of tetraphenylphosphonium (TPP + ) in response to a transmembrane potential (δψ tm ). The 2 H quadrupolar splittings (δν Q 's) measured reflect the level of TPP + bound at the membrane surface due to the latter's effect on the membrane surface electrostatic potential, ψ s . Results reveal the appearance of two distinct δν Q 's, due to differences in bound TPP + at the inner versus the outer monolayer in response to a δψ tm . The observed values of the δν Q 's agree with theoretical predictions based on a derived mathematical model that takes into account δψ tm , plus ψ s , plus the equilibrium binding of TPP + from solution onto the membrane surface, plus the sensitivity of δν Q to the amount of bound TPP + . This model identifies experimental factors that lead to improvements in spectral resolution. Henceforth, 2 H NMR is a valuable tool for quantifying transmembrane asymmetries of ψ s . (author)

  2. Giant resonance spectroscopy of 40Ca with the (e,e'x) reaction (III): Direct versus statistical decay

    International Nuclear Information System (INIS)

    Carter, J.; Diesener, H.; Helm, U.; Herbert, G.; Neumann-Cosel, P. von; Richter, A.; Schrieder, G.; Strauch, S.

    2001-01-01

    The present article is the third out of three on a study of the 40 Ca(e,e'x) reaction discussing the role of direct and statistical contributions to the decay of the observed giant resonance strengths. The proton and α decay modes leading to low-lying final states in 36 Ar and 39 K were investigated. The branching ratios for the p 0 , p 123 , α 0 and α 1 channels are compared to statistical model calculations. In the excitation region of dominant isoscalar E2 strength (E x =12-18 MeV) good agreement is observed. Model predictions of direct E2 decay for the (α 0 +α 1 )/(p 0 +p 1 ) ratio describe the data poorly. In the isovector E1 excitation region large excess strength is found in the population of low-lying states in 39 K. A fluctuation analysis shows the direct contributions to the p 0 , p 1 channels to be ≥85%. The presence of preequilibrium components is indicated by the significant nonstatistical decay to the p 3 level which has a dominant 'phonon·hole' structure. Cross correlations reveal no significant branching between the different channels. The correlations between different electron scattering angles in the p 0 , p 1 and p 3 decay result in an interaction radius compatible with the whole nucleus acting as an emitting source

  3. Dipole-dipole dispersion interactions between neutrons

    OpenAIRE

    Babb, James F.; Higa, Renato; Hussein, Mahir S.

    2016-01-01

    We investigate the long-range interactions between two neutrons utilizing recent data on the neutron static and dynamic electric and magnetic dipole polarizabilities. The resulting long-range potentials are used to make quantitative comparisons between the collisions of a neutron with a neutron and a neutron with a proton. We also assess the importance of the first pion production threshold and first excited state of the nucleon, the $\\Delta$-resonance ($J^{\\pi}$ = + 3/2, I = 3/2). We found b...

  4. Giant intracranial aneurysms; Magnetic resonance imaging follow-up and clinical symptoms

    Energy Technology Data Exchange (ETDEWEB)

    Kondoh, Takeshi; Fujita, Katsuzo; Tamaki, Norihiko; Matsumoto, Satoshi [Kobe Univ. (Japan). School of Medicine; Yamashita, Haruo; Shirakata, Masaya

    1991-06-01

    Twenty-four intracranial aneurysms over 20 mm in diameter were studied with magnetic resonance (MR) imaging. MR imaging follow-up of eight cases revealed induced thrombus with homogeneous intensity and decreased size even after complete intraluminal thrombosis. Most cases demonstrated homogeneous intensity thrombus in contrast to the heterogeneous intensity of spontaneous thrombus. The clinical symptoms could not be explained retrospectively by the thrombus characteristics. Perianeurysmal high intensity, indicating cerebral edema, was detected in one case presenting with a rapid increase in size. MR imaging is useful for following these pathological intra- and perianeurysmal changes. (author).

  5. Electric and magnetic dipole transitions from broad s-wave neutron resonance in even-even sd-shell nuclei

    International Nuclear Information System (INIS)

    Kitazawa, H.; Igashira, M.; Shimizu, M.; Muto, K.; Oda, T.; Achiha, Y.; Lee, Y.; Mukai, N.

    1992-01-01

    Observations have been performed for electromagnetic transitions from the broad s-wave neutron resonances at 658 keV in 24 Mg, at 180 keV in 28 Si, and at 103 keV in 32 S. Capture gamma rays were measured with an anti-Compton NaI(Tl) detector, using a neutron time-of-flight technique. E1 and M1 transitions from those resonances to low-lying states with a strong single-particle character were found. The deduced partial radiative widths for E1 transition are in excellent agreement with the Lane-Mughabghab valence-capture model calculations taking the neutron effective charge, -Ze/A. Moreover, it is shown that essential features of the observed E1 and M1 transitions can be well explained by assuming a configuration-mixing wave function, Ψ i (1/2 + )=a(0 + direct-product 1/2 + )+b(1 + direct-product 1/2 + )+c(1 + direct-product 3/2 + ), for each resonance. The M1 transition strengths are compared also with more detailed shell model calculations in the model space of full (sd) n configurations, using the Wildenthal effective interaction

  6. Electric-dipole moment of CaF by molecular-beam, laser-rf, double-resonance study of Stark splittings

    International Nuclear Information System (INIS)

    Childs, W.J.; Goodman, L.S.; Nielsen, U.; Pfeufer, V.

    1984-01-01

    The electronic structure of diatomic molecules is much more complex for open-shell sytems (radicals) than for the normal closed-shell systems, and the development of an adequate theoretical understanding will require a substantial upgrading of experimental knowledge in both quality and quantity. The alkaline-earth monohalide family of radicals, with only a single electron outside closed-shell cores, would appear to be a logical starting point for such studies, and there has been a great increase in work in this area in the last few years in spite of the special difficulties of working with free radicals. As the work of measuring the vibrational and rotational structure of the electronic states has become more complete, attention has turned to study of the much weaker spin-rotation and hyperfine interactions. Within the last three years, these interactions have been studied systematically at high precision in the calcium monohalide family with the molecular-beam, laser-rf double-resonance technique. The same method has now been modified and extended to make possible measurement of the electric-dipole moments of these molecules through observation of the Stark splittings of radiofrequency transitions. It is hoped that when considered together, the several types of data will make it possible to understand the ground-state electronic wave functions of these molecules at least qualitatively. 2 figures

  7. Role of the low-lying isoscalar dipole modes in the polarization potential

    International Nuclear Information System (INIS)

    Bal'butsev, E.B.; Unzhakova, A.V.; Lanza, E.G.; Catania Univ.

    1994-01-01

    An analysis of the real and imaginary parts of the polarization potential in terms of the relative contributions of the single collective states for the 208 Pb + 208 Pb system has been done. The polarization potential has been calculated within the Feshbach formalism taking into account the collective states calculated with the Wigner function moments method. The contribution of the isoscalar giant dipole resonance states has been estimated being of the order of 10-20% of the total at relatively low incident energy. 14 refs., 4 figs., 1 tab

  8. Study of Gamow-Teller giant resonance in /sup 90/Nb by the /sup 90/Zr(/sup 3/He,t)/sup 90/Nb reaction at 90 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, M.; Fujita, Y.; Katayama, I.; Morinobu, S.; Yamazaki, T.; Itahashi, T.; Ikegami, H. [Osaka Univ., Suita (Japan). Research Center for Nuclear Physics; Hayakawa, S. I.; Ikegami, Hidetsugu; Muraoka, Mitsuo [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

    1980-01-01

    A Gamow-Teller giant resonance in /sup 90/Nb was excited by the /sup 90/Zr(/sup 3/He, t) reaction at 89.5 MeV. The strength of the resonance was localized in the energy region of Ex = 4.5 - 7.5 MeV. The transition was found to be dominated by the L = 2 transfer.

  9. Isotopic Dependence of the Giant Monopole Resonance in the Even-A 112-124Sn Isotopes and the Asymmetry Term in Nuclear Incompressibility

    International Nuclear Information System (INIS)

    Li, T.; Garg, U.; Liu, Y.; Marks, R.; Nayak, B. K.; Rao, P. V. Madhusudhana; Fujiwara, M.; Hashimoto, H.; Kawase, K.; Nakanishi, K.; Okumura, S.; Yosoi, M.; Itoh, M.; Ichikawa, M.; Matsuo, R.; Terazono, T.; Uchida, M.; Kawabata, T.; Akimune, H.; Iwao, Y.

    2007-01-01

    The strength distributions of the giant monopole resonance (GMR) have been measured in the even-A Sn isotopes (A=112-124) with inelastic scattering of 400-MeV α particles in the angular range 0 deg. - 8.5 deg. We find that the experimentally observed GMR energies of the Sn isotopes are lower than the values predicted by theoretical calculations that reproduce the GMR energies in 208 Pb and 90 Zr very well. From the GMR data, a value of K τ =-550±100 MeV is obtained for the asymmetry term in the nuclear incompressibility

  10. Isotopic Dependence of the Giant Monopole Resonance in the Even-A Sn112 124 Isotopes and the Asymmetry Term in Nuclear Incompressibility

    Science.gov (United States)

    Li, T.; Garg, U.; Liu, Y.; Marks, R.; Nayak, B. K.; Rao, P. V. Madhusudhana; Fujiwara, M.; Hashimoto, H.; Kawase, K.; Nakanishi, K.; Okumura, S.; Yosoi, M.; Itoh, M.; Ichikawa, M.; Matsuo, R.; Terazono, T.; Uchida, M.; Kawabata, T.; Akimune, H.; Iwao, Y.; Murakami, T.; Sakaguchi, H.; Terashima, S.; Yasuda, Y.; Zenihiro, J.; Harakeh, M. N.

    2007-10-01

    The strength distributions of the giant monopole resonance (GMR) have been measured in the even-A Sn isotopes (A=112 124) with inelastic scattering of 400-MeV α particles in the angular range 0° 8.5°. We find that the experimentally observed GMR energies of the Sn isotopes are lower than the values predicted by theoretical calculations that reproduce the GMR energies in Pb208 and Zr90 very well. From the GMR data, a value of Kτ=-550±100MeV is obtained for the asymmetry term in the nuclear incompressibility.

  11. Testing the mutually enhanced magicity effect in nuclear incompressibility via the giant monopole resonance in the {sup 204,206,208}Pb isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Patel, D. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Garg, U., E-mail: garg@nd.edu [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Fujiwara, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Adachi, T. [Kernfysisch Versneller Instituut, University of Groningen, 9747 AA Groningen (Netherlands); Akimune, H. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Berg, G.P.A. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Harakeh, M.N. [Kernfysisch Versneller Instituut, University of Groningen, 9747 AA Groningen (Netherlands); GANIL, CEA/DSM-CNRS/IN2P3, 14076 Cean (France); Itoh, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Iwamoto, C. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Long, A.; Matta, J.T. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Murakami, T. [Division of Physics and Astronomy, Kyoto University, Kyoto 606-8502 (Japan); Okamoto, A. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Sault, K. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Talwar, R. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Uchida, M. [Department of Physics, Tokyo Institute of Technology, Tokyo 152-8850 (Japan); and others

    2013-10-07

    Using inelastic α-scattering at extremely forward angles, including 0°, the strength distributions of the isoscalar giant monopole resonance (ISGMR) have been measured in the {sup 204,206,208}Pb isotopes in order to examine the proposed mutually enhanced magicity (MEM) effect on the nuclear incompressibility. The MEM effect had been suggested as a likely explanation of the “softness” of nuclear incompressibility observed in the ISGMR measurements in the Sn and Cd isotopes. Our experimental results rule out any manifestation of the MEM effect in nuclear incompressibility and leave the question of the softness of the open-shell nuclei unresolved still.

  12. Wavelet signatures of K-splitting of the Isoscalar Giant Quadrupole Resonance in deformed nuclei from high-resolution (p,p‧) scattering off 146, 148, 150Nd

    Science.gov (United States)

    Kureba, C. O.; Buthelezi, Z.; Carter, J.; Cooper, G. R. J.; Fearick, R. W.; Förtsch, S. V.; Jingo, M.; Kleinig, W.; Krugmann, A.; Krumbolz, A. M.; Kvasil, J.; Mabiala, J.; Mira, J. P.; Nesterenko, V. O.; von Neumann-Cosel, P.; Neveling, R.; Papka, P.; Reinhard, P.-G.; Richter, A.; Sideras-Haddad, E.; Smit, F. D.; Steyn, G. F.; Swartz, J. A.; Tamii, A.; Usman, I. T.

    2018-04-01

    The phenomenon of fine structure of the Isoscalar Giant Quadrupole Resonance (ISGQR) has been studied with high energy-resolution proton inelastic scattering at iThemba LABS in the chain of stable even-mass Nd isotopes covering the transition from spherical to deformed ground states. A wavelet analysis of the background-subtracted spectra in the deformed 146, 148, 150Nd isotopes reveals characteristic scales in correspondence with scales obtained from a Skyrme RPA calculation using the SVmas10 parameterization. A semblance analysis shows that these scales arise from the energy shift between the main fragments of the K = 0 , 1 and K = 2 components.

  13. Time Dependent Density Functional Theory description of giant resonances in transition metal complexes: The photoionization dynamics of Cr(CO)6

    International Nuclear Information System (INIS)

    Stener, M.; Fronzoni, G.; Decleva, P.

    2009-01-01

    The photoionization dynamics of Cr(CO) 6 has been calculated at the TDDFT level, employing a basis set of multicentric B-spline functions with the explicit treatment of the photoelectron continuum. The cross section and the asymmetry parameter profiles of all the valence orbitals have been considered and compared with the available experimental data. The most interesting spectral feature is the intense autoionization resonance Cr 3p → Cr 3d observed in the experiment of band A, which is very well reproduced by present calculation at the TDDFT level. Other observed spectral features have been ascribed to shape resonances and assigned according to the dipole-prepared continuum orbital nature. The present TDDFT scheme proves accurate and practicable on large and complex systems containing transition metal compounds, for the description and the interpretation of the photoionization dynamics.

  14. Decay of the isoscalar 1(h/2π)ω giant E3 resonance in 92Mo

    International Nuclear Information System (INIS)

    Klein, R.A.

    1984-01-01

    By means of the Heidelberg tandem-post accelerator combination the decay of the isoscalar 1 (h/2π)ω giant E3 resonance (LEOR) in 92 Mo was studied by (α, α', γ) coincidence measurements. At an incident energy of 50.4 MeV of the α particles the scattered helium nuclei were spectroscoped by eight semiconductor detectors in a maximum of the L=3 angular distribution. The γ quanta emitted coincidently by the excited target nuclei were detected in three high-resolution Ge diodes. Because of the good resolution both in the alpha and in the gamma branch for about 30 states in the excitation energy range of 1-7 MeV branching ratios for the gamma decay could be measured. For 16 of these levels lifetimes were determined by the Doppler-shift attenuation method. Starting from the determined branching ratios and typical lifetimes (40-90 fs) for 3 - states in the excitation-energy range of the LEOR (5-10 MeV) an earlier reported strong ground-state decay (8%) of the LEOR can be excluded. Rather the LEOR decays so as it is expected by the model of the statistical decay namely dominantly to low-lying 3 - , 4 - , and above all 5 - levels. A likewise reported strong E1-decay of the LEOR to the 2 + 1 state in 90 Zr which is implicated in the framework of a collective model in connection with the E3 ground-state transitions can in 92 Mo also not be confirmed. In spite of the strongly collective nature of the first 2 + state in 92 Mo an increased LEOR decay to this level was not observed. Against that in the LEOR region ground-state transitions of 1 - states with isoscalar nature were spectroscoped. The observation of these levels is also reproduced by performed RPA calculations. A parallel measurement on 90 Zr confirms the results of this thesis. (orig./HSI) [de

  15. Dipole-dipole dispersion interactions between neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Babb, James F. [Harvard-Smithsonian Center for Astrophysics, ITAMP, Cambridge, MA (United States); Higa, Renato [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo (Brazil); Hussein, Mahir S. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo (Brazil); Universidade de Sao Paulo, Instituto de Estudos Avancados, Sao Paulo (Brazil); Departamento de Fisica, Instituto Tecnologico de Aeronautica, CTA, Sao Jose dos Campos (Brazil)

    2017-06-15

    We investigate the long-range interactions between two neutrons utilizing recent data on the neutron static and dynamic electric and magnetic dipole polarizabilities. The resulting long-range potentials are used to make quantitative comparisons between the collisions of a neutron with a neutron and a neutron with a proton. We also assess the importance of the first pion production threshold and first excited state of the nucleon, the Δ-resonance (J{sup π} = +3/2, I = 3/2). We found both dynamical effects to be quite relevant for distances r between ∝ 50 fm up to ∝ 10{sup 3} fm in the nn system, the neutron-wall system and in the wall-neutron-wall system, reaching the expected asymptotic limit beyond that. Relevance of our findings to the confinement of ultra cold neutrons inside bottles is discussed. (orig.)

  16. Test of Axel-Brink predictions by a discrete approach to resonance-averaged (n,γ) spectroscopy

    International Nuclear Information System (INIS)

    Raman, S.; Shahal, O.; Slaughter, G.G.

    1981-01-01

    The limitations imposed by Porter-Thomas fluctuations in the study of primary γ rays following neutron capture have been partly overcome by obtaining individual γ-ray spectra from 48 resonances in the 173 Yb(n,γ) reaction and summing them after appropriate normalizations. The resulting average radiation widths (and hence the γ-ray strength function) are in good agreement with the Axel-Brink predictions based on a giant dipole resonance model

  17. Description of giant resonances

    International Nuclear Information System (INIS)

    Lane, A.M.

    1975-01-01

    The history of collective theories in nuclear physics is briefly reviewed. It is emphasised that some theories (like RPA) allow collectivity to emerge from calculations, while others (like GCM) essentially impose a collective framework from teh start. The former class has the incidental merit that it treats spreading of collective states arising from interaction with (discrete and continuum) particle excitations. A problem with the RPA calculations is that they are almost too detailed if one's interest is in exposing systematic qualitative features. The speaker (along with co-authors) has developed a sum-rule method for exposing such trends. It is based on the fact that one can readily evaluate three sum-rules; in addition to the familiar one with plus-one power of energy-weighting, those with minus-one and plus-three powers can be evaluated for RPA states in closed form. From the three moments, the energy and spread of the collective state can be obtained. Amongst other things, the approach gives a very simple derivation of the Suzuki-Mottelson result that collective energy equals √2 times the oscillator quantum. (orig.) [de

  18. USING SCHUMANN RESONANCE MEASUREMENTS FOR CONSTRAINING THE WATER ABUNDANCE ON THE GIANT PLANETS-IMPLICATIONS FOR THE SOLAR SYSTEM'S FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Simoes, Fernando; Pfaff, Robert; Klenzing, Jeffrey; Freudenreich, Henry; Bromund, Kenneth; Martin, Steven; Rowland, Douglas [NASA/GSFC, Heliophysics Science Division, Space Weather Laboratory (Code 674), Greenbelt, MD (United States); Hamelin, Michel; Berthelier, Jean-Jacques [LATMOS/IPSL, UPMC, Paris (France); Beghin, Christian; Lebreton, Jean-Pierre [LPC2E, CNRS/Universite d' Orleans (France); Grard, Rejean [ESA/ESTEC, Research Scientific Support Department, Noordwijk (Netherlands); Sentman, Davis [Institute of Geophysics, University of Alaska Fairbanks, Fairbanks, AK (United States); Takahashi, Yukihiro [Department of Geophysics, Tohoku University, Sendai (Japan); Yair, Yoav [Department Life Natural Sciences, Open University of Israel, Raanana (Israel)

    2012-05-01

    The formation and evolution of the solar system is closely related to the abundance of volatiles, namely water, ammonia, and methane in the protoplanetary disk. Accurate measurement of volatiles in the solar system is therefore important for understanding not only the nebular hypothesis and origin of life but also planetary cosmogony as a whole. In this work, we propose a new remote sensing technique to infer the outer planets' water content by measuring Tremendously and Extremely Low Frequency (TLF-ELF) electromagnetic wave characteristics (Schumann resonances) excited by lightning in their gaseous envelopes. Schumann resonance detection can be potentially used for constraining the uncertainty of volatiles of the giant planets, mainly Uranus and Neptune, because such TLF-ELF wave signatures are closely related to the electric conductivity profile and water content.

  19. Destruction of /sup 18/O in red giants. A search for a sub-threshold resonance in the /sup 18/O+p system

    Energy Technology Data Exchange (ETDEWEB)

    Champagne, A E; Pitt, M L

    1986-09-08

    The /sup 18/O(/sup 3/He,d)/sup 19/F reaction has been used to determine if a presumed sub-threshold resonance at Esub(c.m.)=-94 KeV in the /sup 18/O(p,..cap alpha..)/sup 15/N reaction exists at an astrophysically significant level. No evidence for this state was observed which implies a dimensionless reduced width thetasub(p)/sup 2/<5 . 10/sup -5/. In addition, a proton width GAMMAsub(p)=2 x 10/sup -19/ eV has been determined for a d-wave resonance located at Esub(c.m.)=20 keV. The resulting thermonuclear reaction rate is slow enough to ensure that /sup 18/O is not destroyed at red-giant temperatures.

  20. Contribution of giant resonances in elastic and inelastic scattering of polarized protons on 12C between 19 and 23MeV

    International Nuclear Information System (INIS)

    Gaillard, Y.R.

    1975-01-01

    Angular distributions of analyzing power and differential cross section have been measured for the elastic and inelastic scattering of polarized protons on 12 C, up to 12.7MeV excitation energy. Incident energy varied from 19 to 23MeV by steps of about 200keV, the cyclotron beam energy, varying by steps of about 1MeV, was measured using crossover techniques. Fine steps of energy were obtained by use of carbon absorbers. Elastic scattering data were analyzed using a linear energy-dependent optical model. Data for the level at 4.4MeV excitation energy were analyzed using coupled channel calculations. Preliminary results for the level (1 - , Esub(x)=12.7MeV) were analyzed including giant resonances as doorways states in inelastic scattering, according to Geramb-Amos formalism. This analysis shows that it should be possible to study high-lying giant resonances through their contribution to low-lying state excitation [fr

  1. Dipole and spin-dipole strength distributions in isotopes

    Indian Academy of Sciences (India)

    Necla Cakmak

    2018-01-03

    Jan 3, 2018 ... isotopes. NECLA CAKMAK1, SADIYE CAKMAK2, CEVAD SELAM3 and SERDAR UNLU4,∗. 1Department of Physics, Karabuk University, Karabuk, Turkey. 2Department of Physics ... and 14 and the giant resonances in the energy region of. 19–27 MeV were ... even–even nuclei [21]. The restoration of this ...

  2. Electric-dipole absorption resonating with longitudinal optical phonon-plasmon system and its effect on dispersion relations of interface phonon polariton modes in metal/semiconductor-stripe structures

    Science.gov (United States)

    Sakamoto, Hironori; Takeuchi, Eito; Yoshida, Kouki; Morita, Ken; Ma, Bei; Ishitani, Yoshihiro

    2018-01-01

    Interface phonon polaritons (IPhPs) in nano-structures excluding metal components are thoroughly investigated because they have lower loss in optical emission or absorption and higher quality factors than surface plasmon polaritons. In previous reports, it is found that strong infrared (IR) absorption is based on the interaction of p-polarized light and materials, and the resonance photon energy highly depends on the structure size and angle of incidence. We report the optical absorption by metal/semiconductor (bulk-GaAs and thin film-AlN)-stripe structures in THz to mid-IR region for the electric field of light perpendicular to the stripes, where both of s- and p-polarized light are absorbed. The absorption resonates with longitudinal optical (LO) phonon or LO phonon-plasmon coupling (LOPC) modes, and thus is independent of the angle of incidence or structure size. This absorption is attributed to the electric dipoles by the optically induced polarization charges at the metal/semiconductor, heterointerfaces, or interfaces of high electron density layers and depression ones. The electric permittivity is modified by the formation of these dipoles. It is found to be indispensable to utilize our form of altered permittivity to explain the experimental dispersion relations of metal/semiconductor-IPhP and SPhP in these samples. This analysis reveals that the IPhPs in the stripe structures of metal/AlN-film on a SiC substrate are highly confined in the AlN film, while the permittivity of the structures of metal/bulk-GaAs is partially affected by the electric-dipoles. The quality factors of the electric-dipole absorption are found to be 42-54 for undoped samples, and the value of 62 is obtained for Al/AlN-IPhP. It is thought that metal-contained structures are not obstacles to mode energy selectivity in phonon energy region of semiconductors.

  3. Electromagnetic dipole and Gamow-Teller responses of even and odd {sup 90-94}{sub 40}Zr isotopes in QRPA calculations with the D1M Gogny force

    Energy Technology Data Exchange (ETDEWEB)

    Deloncle, I. [CSNSM, CNRS et Universite Paris-Sud, Orsay (France); CEA, DAM, DIF, Arpajon (France); Peru, S. [CEA, DAM, DIF, Arpajon (France); Martini, M. [ESNT, CEA-Saclay, DSM, Irfu, Service de Physique Nucleaire, Gif-sur-Yvette (France)

    2017-08-15

    In this paper we present theoretical results on the dipole response in the proton spin-saturated {sup 90-94}Zr isotopes. The electric and magnetic dipole excitations are obtained in Hartree-Fock-Bogolyubov plus Quasi-particle Random Phase Approximation (QRPA) calculations performed with the D1M Gogny force. A pnQRPA charge exchange code is used to study the Gamow-Teller response. The results on the pygmy, the giant dipole resonances as well as those on the magnetic nuclear spin-flip excitation and the Gamow-Teller transitions are compared with available experimental or theoretical information. In our approach, the proton pairing plays a role in the phonon excitations, in particular in the M1 nuclear spin-flip resonance. (orig.)

  4. Strength decoupling from the giant dipole resonance upon diagonalizing a Gaussian force and a delta-force on a particle-hole basis

    International Nuclear Information System (INIS)

    Csernai, L.P.; Zimanyi, J.; Gyarmati, B.; Lovas, R.G.

    1978-01-01

    The finite-range Gaussian force and delta-force have been diagonalized in a basis of 27 particle-hole states with Jsup(π)=1 - in 116 Sn. Depending on the range of the force, 3.9-7.1% of the total transition rate has been found in the 6-9 MeV excitation energy region, which comprises the unperturbed energies of the basis states containing neutron threshold states. (Auth.)

  5. The analysis and evaluation by the method of reduction of total photoneutron reaction cross sections in the range of giant dipole resonance

    International Nuclear Information System (INIS)

    Varlamov, V.V.; Efimkin, N.G.; Ishkhanov, B.S.; Sapunenko, V.V.; Stepanov, M.E.

    1993-01-01

    The method based on the method of reduction is proposed for the evaluation of photonuclear reaction cross sections have been obtained at significant systematic uncertainties (different apparatus functions, calibration and normalization uncertainties). The evaluation method consists of using the real apparatus function (photon spectrum) of each individual experiment to reduce the data to a representation generated by an apparatus function of better quality. The task is to find the most reasonably achievable monoenergetic representation (MRAMR) of the information about cross section contained in different experiment observables and to take into account the experimental uncertainties of calibration and normalization procedures. The method was used to obtain the evaluated total photoneutron (γ, xn) reaction cross sections for 16 O, 28 Si, nat Cu, 141 Pr, and 208 Pb are presented. 79 refs., 19 figs., 6 tabs

  6. Measurement of the /sup 12/C(n,γ0)/sup 13/C cross section in the giant dipole resonance region

    International Nuclear Information System (INIS)

    August, R.A.; Weller, H.R.; Tilley, D.R.

    1987-01-01

    The /sup 12/C(n,γ 0 ) /sup 13/C excitation function at 90 0 has been measured for neutron energies from 6.5 to 18.5 MeV. Whereas previous measurements disagreed at the lower energies with a direct-semidirect capture calculation based on /sup 12/C(p,γ 0 ) /sup 13/N data, the present results, especially when the uncertainty in absolute cross section is considered, indicate reasonable qualitative agreement with the calculation

  7. Dynamic dipole-dipole interactions between excitons in quantum dots of different sizes

    DEFF Research Database (Denmark)

    Matsueda, Hideaki; Leosson, Kristjan; Xu, Zhangcheng

    2004-01-01

    A model of the resonance dynamic dipole-dipole interaction between excitons confined in quantum dots (QDs) of different sizes at close enough distance is given in terms of parity inheritance and exchange of virtual photons. Microphotoluminescence spectra of GaAs-AlGaAs coupled QDs are proposed to...

  8. Dynamic Dipole-Dipole Interactions between Excitons in Quantum Dots of Different Sizes

    DEFF Research Database (Denmark)

    Matsueda, Hideaki; Leosson, Kristjan; Xu, Zhangcheng

    2005-01-01

    Micro-photoluminescence spectra of GaAs/AlGaAs coupled quantum dots (QDs) are given, and proposed to be analyzed by our resonance dynamic dipole-dipole interaction (RDDDI) model, based on parity inheritance and exchange of virtual photons among QDs of different sizes....

  9. Systematic study of the giant monopolar resonance via inelastic scattering of 108.5 MeV 3He. Measurement of the nuclear compressibility

    International Nuclear Information System (INIS)

    Lebrun, Didier.

    1981-09-01

    The giant monopole resonance has been studied via inelastic scattering of 108.5 MeV 3 He at very small angles (including 0 0 ) on approximately 50 nuclei. Its angular distribution reaches its maximum in this region and leads to clear separation with GQR. DWBA analysis shows a smooth increase of the strength from few per cent of the sum rule in light nuclei up to 100% in heavier ones. The excitation energy analysis shows a crossing effect of the monopole and quadrupole frequencies in A = 40-50 region, a coupling effect between the two modes in deformed nuclei, an asymmetry effect in several series of isotopes. Compressibility moduli of nuclear matter Ksub(infinity), surface Ksub(s) and asymmetry Ksub(tau) have seen extracted, as well as the Landau parameter F 0 at saturation [fr

  10. Giant monopole resonance in even-A Cd isotopes, the asymmetry term in nuclear incompressibility, and the 'softness' of Sn and Cd nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Patel, D. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Garg, U., E-mail: garg@nd.edu [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Fujiwara, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Akimune, H. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Berg, G.P.A. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Harakeh, M.N. [Kernfysisch Versneller Instituut, University of Groningen, 9747 AA Groningen (Netherlands); Itoh, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Kawabata, T. [Center for Nuclear Studies, University of Tokyo, Tokyo 113-0033 (Japan); Kawase, K. [Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047 (Japan); Nayak, B.K. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Ohta, T. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Ouchi, H. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Piekarewicz, J. [Department of Physics, Florida State University, Tallahassee, FL 32306 (United States); Uchida, M. [Department of Physics, Tokyo Institute of Technology, Tokyo 152-8850 (Japan); Yoshida, H.P. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Yosoi, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan)

    2012-12-05

    The isoscalar giant monopole resonance (ISGMR) in even-A Cd isotopes has been studied by inelastic {alpha}-scattering at 100 MeV/u and at extremely forward angles, including 0 Degree-Sign . The asymmetry term in the nuclear incompressibility extracted from the ISGMR in Cd isotopes is found to be K{sub {tau}}=-555{+-}75 MeV, confirming the value previously obtained from the Sn isotopes. ISGMR strength has been computed in relativistic RPA using NL3 and FSUGold effective interactions. Both models significantly overestimate the centroids of the ISGMR strength in the Cd isotopes. Combined with other recent theoretical effort, the question of the 'softness' of the open-shell nuclei in the tin region remains open still.

  11. Pygmy and core polarization dipole modes in 206Pb: Connecting nuclear structure to stellar nucleosynthesis

    Science.gov (United States)

    Tonchev, A. P.; Tsoneva, N.; Bhatia, C.; Arnold, C. W.; Goriely, S.; Hammond, S. L.; Kelley, J. H.; Kwan, E.; Lenske, H.; Piekarewicz, J.; Raut, R.; Rusev, G.; Shizuma, T.; Tornow, W.

    2017-10-01

    A high-resolution study of the electromagnetic response of 206Pb below the neutron separation energy is performed using a (γ → ,γ‧) experiment at the HI γ → S facility. Nuclear resonance fluorescence with 100% linearly polarized photon beams is used to measure spins, parities, branching ratios, and decay widths of excited states in 206Pb from 4.9 to 8.1 MeV. The extracted ΣB (E 1) ↑ and ΣB (M 1) ↑ values for the total electric and magnetic dipole strength below the neutron separation energy are 0.9 ± 0.2 e2fm2 and 8.3 ± 2.0 μN2, respectively. These measurements are found to be in very good agreement with the predictions from an energy-density functional (EDF) plus quasiparticle phonon model (QPM). Such a detailed theoretical analysis allows to separate the pygmy dipole resonance from both the tail of the giant dipole resonance and multi-phonon excitations. Combined with earlier photonuclear experiments above the neutron separation energy, one extracts a value for the electric dipole polarizability of 206Pb of αD = 122 ± 10 mb /MeV. When compared to predictions from both the EDF+QPM and accurately calibrated relativistic EDFs, one deduces a range for the neutron-skin thickness of Rskin206 = 0.12- 0.19 fm and a corresponding range for the slope of the symmetry energy of L = 48- 60 MeV. This newly obtained information is also used to estimate the Maxwellian-averaged radiative cross section 205Pb (n , γ)206Pb at 30 keV to be σ = 130 ± 25 mb. The astrophysical impact of this measurement-on both the s-process in stellar nucleosynthesis and on the equation of state of neutron-rich matter-is discussed.

  12. Relativistic quasiparticle time blocking approximation: Dipole response of open-shell nuclei

    International Nuclear Information System (INIS)

    Litvinova, E.; Ring, P.; Tselyaev, V.

    2008-01-01

    The self-consistent relativistic quasiparticle random-phase approximation (RQRPA) is extended by the quasiparticle-phonon coupling (QPC) model using the quasiparticle time blocking approximation (QTBA). The method is formulated in terms of the Bethe-Salpeter equation (BSE) in the two-quasiparticle space with an energy-dependent two-quasiparticle residual interaction. This equation is solved either in the basis of Dirac states forming the self-consistent solution of the ground state or in the momentum representation. Pairing correlations are treated within the Bardeen-Cooper-Schrieffer (BCS) model with a monopole-monopole interaction. The same NL3 set of the coupling constants generates the Dirac-Hartree-BCS single-quasiparticle spectrum, the static part of the residual two-quasiparticle interaction and the quasiparticle-phonon coupling amplitudes. A quantitative description of electric dipole excitations in the chain of tin isotopes (Z=50) with the mass numbers A=100,106,114,116,120, and 130 and in the chain of isotones with (N=50) 88 Sr, 90 Zr, 92 Mo is performed within this framework. The RQRPA extended by the coupling to collective vibrations generates spectra with a multitude of 2q x phonon (two quasiparticles plus phonon) states providing a noticeable fragmentation of the giant dipole resonance as well as of the soft dipole mode (pygmy resonance) in the nuclei under investigation. The results obtained for the photo absorption cross sections and for the integrated contributions of the low-lying strength to the calculated dipole spectra agree very well with the available experimental data

  13. Inhibition of two-photon absorption due to dipole-dipole interaction in nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Mahi R. [Department of Physics and Astronomy, University of Western Ontario, London, N6A 3K7 (Canada)], E-mail: msingh@uwo.ca

    2008-07-21

    We have investigated the inhibition of two-photon absorption in photonic crystals doped with an ensemble of four-level nanoparticles. The particles are interacting with one another by the dipole-dipole interaction. Dipoles in nanoparticles are induced by a selected transition. Numerical simulations have been performed for an isotropic photonic crystal. Interesting phenomena have been predicted such as the inhibition of the two-photon absorption due to the dipole-dipole interaction. It has also been found that the inhibition effect can be switched on and off by tuning a decay resonance energy within the energy band of the crystal. A theory of dressed states has been used to explain the results.

  14. X-ray excited photoluminescence near the giant resonance in solid-solution Gd(1-x)Tb(x)OCl nanocrystals and their retention upon solvothermal topotactic transformation to Gd(1-x)Tb(x)F3.

    Science.gov (United States)

    Waetzig, Gregory R; Horrocks, Gregory A; Jude, Joshua W; Zuin, Lucia; Banerjee, Sarbajit

    2016-01-14

    Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb(3+) centers upon excitation in proximity to the giant resonance of the host Gd(3+) ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism from multiple exciton generation to single thermal exciton formation and Auger decay processes. The solid-solution Gd1-xTbxOCl nanocrystals are further topotactically transformed with retention of a nine-coordinated cation environment to solid-solution Gd1-xTbxF3 nanocrystals upon solvothermal treatment with XeF2. The metastable hexagonal phase of GdF3 can be stabilized at room temperature through this topotactic approach and is transformed subsequently to the orthorhombic phase. The fluoride nanocrystals indicate an analogous but blue-shifted modulation of the X-ray excited optical luminescence of the Tb(3+) centers upon X-ray excitation near the giant resonance of the host Gd(3+) ions.

  15. Giant grains

    International Nuclear Information System (INIS)

    Leitch-Devlin, M.A.; Millar, T.J.; Williams, D.A.

    1976-01-01

    Infrared observations of the Orion nebula have been interpreted by Rowan-Robinson (1975) to imply the existence of 'giant' grains, radius approximately 10 -2 cm, throughout a volume about a parsec in diameter. Although Rowan-Robinson's model of the nebula has been criticized and the presence of such grains in Orion is disputed, the proposition is accepted, that they exist, and in this paper situations in which giant grains could arise are examined. It is found that, while a giant-grain component to the interstellar grain density may exist, it is difficult to understand how giant grains arise to the extent apparently required by the Orion nebula model. (Auth.)

  16. Investigation of the dipole response of nickel isotopes in the presence of a high-frequency electromagnetic field

    International Nuclear Information System (INIS)

    Rossi, Dominic M.

    2010-01-01

    The electric dipole response of neutron-rich nickel isotopes has been investigated using the LAND setup at GSI in Darmstadt (Germany). Relativistic secondary beams of 56-57 Ni and 67-72 Ni at approximately 500 AMeV have been generated using projectile fragmentation of stable ions on a 4 g/cm 2 Be target and subsequent separation in the magnetic dipole fields of the FRagment Separator (FRS). After reaching the LAND setup in Cave C, the radioactive ions were excited electromagnetically in the electric field of a Pb target. The decay products have been measured in inverse kinematics using various detectors. Neutron-rich 67-69 Ni isotopes decay by the emission of neutrons, which are detected in the LAND detector. The present analysis concentrates on the (γ,n) and (γ,2n) channels in these nuclei, since the proton and three-neutron thresholds are unlikely to be reached considering the virtual photon spectrum for nickel ions at 500 AMeV. A measurement of the stable 58 Ni isotope is used as a benchmark to check the accuracy of the present results with previously published data. The measured (γ,n) and (γ,np) channels are compared with an inclusive photoneutron measurement by Fultz and coworkers, which are consistent within the respective errors. The measured excitation energy distributions of 67-69 Ni contain a large portion of the Giant Dipole Resonance (GDR) strength predicted by the Thomas-Reiche-Kuhn energy-weighted sum rule, as well as a significant amount of low-lying E1 strength, that cannot be attributed to the GDR alone. The GDR distribution parameters are calculated using well-established semi-empirical systematic models, providing the peak energies and widths. The GDR strength is extracted from the χ 2 minimization of the model GDR to the measured data of the (γ,2n) channel, thereby excluding any influence of eventual low-lying strength. The subtraction of the obtained GDR distribution from the total measured E1 strength provides the low-lying E1 strength

  17. Search for a neutron electric dipole moment

    Energy Technology Data Exchange (ETDEWEB)

    Morse, J [Rutherford Appleton Laboratory, Chilton (U.K.)

    1984-03-01

    To search for evidence of a breakdown of symmetry under the time reversal transformation, a magnetic resonance measurement is made to detect an electric dipole moment (EDM) of ultracold neutrons stored for periods approximately= 60s in the presence of a strong electric field. The measured neutron EDM is (0.3 +- 4.8) x 10/sup -25/ ecm.

  18. Strong electric and magnetic dipole excitations in deformed nuclei

    International Nuclear Information System (INIS)

    Kneissl, U.

    1993-01-01

    Systematic nuclear resonance fluorescence (NRF) experiments have been performed at the bremsstrahlung facility of the Stutgart dynamitron to investigate the distribution of magnetic and electric dipole excitations in deformed nuclei

  19. Theoretical Study of Local Surface Plasmon Resonances on a Dielectric-Ag Core-Shell Nanosphere Using the Discrete-Dipole Approximation Method

    International Nuclear Information System (INIS)

    Ma Ye-Wan; Wu Zhao-Wang; Zhang Li-Hua; Liu Wan-Fang; Zhang Jie

    2015-01-01

    The local surface plasmon resonances (LSPRs) of dielectric-Ag core-shell nanospheres are studied by the discretedipole approximation method. The result shows that LSPRs are sensitive to the surrounding medium refractive index, which shows a clear red-shift with the increasing surrounding medium refractive index. A dielectric-Ag core-shell nanosphere exhibits a strong coupling between the core and shell plasmon resonance modes. LSPRs depend on the shell thickness and the composition of dielectric-core and metal-shell. LSPRs can be tuned over a longer wavelength range by changing the ratio of core to shell value. The lower energy mode ω_− shows a red-shift with the increasing dielectric-core value and the inner core radius, while blue-shifted with the increasing outer shell thickness. The underlying mechanisms are analyzed with the plasmon hybridization theory and the phase retardation effect. (paper)

  20. Electric dipole moments reconsidered

    International Nuclear Information System (INIS)

    Rupertsberger, H.

    1989-01-01

    The electric dipole moments of elementary particles, atoms, molecules and their connection to the electric susceptibility are discussed for stationary states. Assuming rotational invariance it is emphasized that for such states only in the case of a parity and time reversal violating interaction the considered particles can obtain a nonvanishing expectation value for the electric dipole moment. 1 fig., 13 refs. (Author)

  1. UNK superconducting dipole development

    International Nuclear Information System (INIS)

    Ageev, A.I.; Andreev, N.I.; Balbekov, V.I.

    1987-01-01

    For choozing the design of superconducting dipoles (SCD) for the IHEP UNK the test results for SCD with warm and cold iron are given. The main parameters of dipoles are presented. The SCD designs are described. At present works on SP magnet simulation for UNK are carried out in two directions. Tests are conducted on a rig with a chain of series dipoles with a warm magnetic screen. The purpose of these tests is to study heat exchange and hydraulics in magnets, energy and helium evacuation in emergency magnet transition into normal conditions, simulation of possible cooling and heating schemes. Another direction involves production of short and full-scale dipole models with cold iron and their testing on rigs. The final choice of the dipole design for commercial production is planned for 1987

  2. Changes in earth's dipole.

    Science.gov (United States)

    Olson, Peter; Amit, Hagay

    2006-11-01

    The dipole moment of Earth's magnetic field has decreased by nearly 9% over the past 150 years and by about 30% over the past 2,000 years according to archeomagnetic measurements. Here, we explore the causes and the implications of this rapid change. Maps of the geomagnetic field on the core-mantle boundary derived from ground-based and satellite measurements reveal that most of the present episode of dipole moment decrease originates in the southern hemisphere. Weakening and equatorward advection of normal polarity magnetic field by the core flow, combined with proliferation and growth of regions where the magnetic polarity is reversed, are reducing the dipole moment on the core-mantle boundary. Growth of these reversed flux regions has occurred over the past century or longer and is associated with the expansion of the South Atlantic Anomaly, a low-intensity region in the geomagnetic field that presents a radiation hazard at satellite altitudes. We address the speculation that the present episode of dipole moment decrease is a precursor to the next geomagnetic polarity reversal. The paleomagnetic record contains a broad spectrum of dipole moment fluctuations with polarity reversals typically occurring during dipole moment lows. However, the dipole moment is stronger today than its long time average, indicating that polarity reversal is not likely unless the current episode of moment decrease continues for a thousand years or more.

  3. X-ray excited photoluminescence near the giant resonance in solid-solution Gd1-xTbxOCl nanocrystals and their retention upon solvothermal topotactic transformation to Gd1-xTbxF3

    Science.gov (United States)

    Waetzig, Gregory R.; Horrocks, Gregory A.; Jude, Joshua W.; Zuin, Lucia; Banerjee, Sarbajit

    2015-12-01

    Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb3+ centers upon excitation in proximity to the giant resonance of the host Gd3+ ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism from multiple exciton generation to single thermal exciton formation and Auger decay processes. The solid-solution Gd1-xTbxOCl nanocrystals are further topotactically transformed with retention of a nine-coordinated cation environment to solid-solution Gd1-xTbxF3 nanocrystals upon solvothermal treatment with XeF2. The metastable hexagonal phase of GdF3 can be stabilized at room temperature through this topotactic approach and is transformed subsequently to the orthorhombic phase. The fluoride nanocrystals indicate an analogous but blue-shifted modulation of the X-ray excited optical luminescence of the Tb3+ centers upon X-ray excitation near the giant resonance of the host Gd3+ ions.Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb3+ centers upon excitation in proximity to the giant resonance of the host Gd3+ ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism

  4. The isovector quadrupole resonance in yttrium excited by neutron radiative capture

    International Nuclear Information System (INIS)

    Zorro, R.; Bergqvist, I.

    1987-01-01

    In order to investigate the properties of the isovector giant quadrupole resonance (ΔT=1, ΔS=0) in the A=90 mass region, gamma-ray spectra from the reaction 89 Y(n,γ) 90 Y were recorded at several neutron energies in the energy range 12 to 27 MeV at 55 0 , 90 0 and 125 0 . The measured fore-aft asymmetry for the ground-state transition is very small in the low-energy region, but becomes appreciable above a neutron energy of 18 MeV. The observed asymmetry is attributed to interference between radiation from the isovector giant quadrupole resonance and radiation of opposite parity (from the high-energy tail of the giant dipole resonance and direct E1 capture). The data obtained in the present work, interpreted in terms of the direct-semidirect capture model, indicate that the excitation energy of the isovector E2 resonance in 90 Y is 26 ± 1 MeV. The data are consistent with a resonance width of 10 ± 2 MeV and with complete exhaustion of the energy-weighted sum rule for the lower isospin component of the resonance. (orig.)

  5. Lepton dipole moments

    CERN Document Server

    Marciano, William J

    2010-01-01

    This book provides a self-contained description of the measurements of the magnetic dipole moments of the electron and muon, along with a discussion of the measurements of the fine structure constant, and the theory associated with magnetic and electric dipole moments. Also included are the searches for a permanent electric dipole moment of the electron, muon, neutron and atomic nuclei. The related topic of the transition moment for lepton flavor violating processes, such as neutrinoless muon or tauon decays, and the search for such processes are included as well. The papers, written by many o

  6. Relation of photofission cross sections and delayed neutron photoproduction in the range of E1-giant resonance. Sootnoshenie mezhdu secheniyami fotodeleniya i fotoobrazovaniya zapazdyvayushchikh nejtronov v oblasti E1-gigantskogo rezonansa

    Energy Technology Data Exchange (ETDEWEB)

    Ganich, P P; Parlag, O A; Sikora, D I; Sychev, S I

    1989-03-01

    Relation between yields and cross sections of photofission and photoproduction is studied in order to use them in the methods for analysis of fissile nuclides. Total yield of delayed neutrons from the {sup 232}Th target and ratios of total yields from {sup 238}U and {sup 232}Th targets were measured in the M=300 microtron in 6-18 MeV energy range. Efficiency of the suggested method for refining the {sup 238}U photofission cross sections in the range of E1-giant resonance is shown.

  7. Some dipole shower studies

    Science.gov (United States)

    Cabouat, Baptiste; Sjöstrand, Torbjörn

    2018-03-01

    Parton showers have become a standard component in the description of high-energy collisions. Nowadays most final-state ones are of the dipole character, wherein a pair of partons branches into three, with energy and momentum preserved inside this subsystem. For initial-state showers a dipole picture is also possible and commonly used, but the older global-recoil strategy remains a valid alternative, wherein larger groups of partons share the energy-momentum preservation task. In this article we introduce and implement a dipole picture also for initial-state radiation in Pythia, and compare with the existing global-recoil one, and with data. For the case of Deeply Inelastic Scattering we can directly compare with matrix element expressions and show that the dipole picture gives a very good description over the whole phase space, at least for the first branching.

  8. Particle electric dipole moments

    CERN Document Server

    Pendlebury, J M

    2000-01-01

    Measurements of particle electric dipole moments (EDMs) continue to put powerful constraints on theories of T-symmetry and CP-symmetry violation, which form currently one of the most prominent fields in particle physics. EDM measurements have been concentrated on neutral systems such as the neutron and atoms and molecules. These measurements allow one to deduce, in turn, the electric dipole moments of the fundamental fermions, that is, the lighter leptons and quarks and also those of some heavy nuclei.

  9. Giant resonance spectroscopy of 40Ca with the (e,e'x) reaction (II): Multipole decomposition of 4π-integrated spectra and angular correlations

    International Nuclear Information System (INIS)

    Diesener, H.; Helm, U.; Huck, V.; Neumann-Cosel, P. von; Rangacharyulu, C.; Richter, A.; Schrieder, G.; Stascheck, A.; Strauch, S.; Ryckebusch, J.; Carter, J.

    2001-01-01

    The present article is the second out of three on a study of the 40 Ca(e,e'x) reaction discussing the multipole decomposition of the measured cross sections and the analysis of angular correlations. The decomposition of the strongly overlapping E0, E1 and E2 giant resonance strengths using the (e,e'x; x=p,α) reaction in 40 Ca is discussed for excitation energies between 10 and about 21 MeV. Two extraction methods are presented based on the variation of the form factors for the different multipoles. The resulting B(E1) strength distribution is in good agreement with (γ,x) photoabsorption data. The summed B(E2) and B(E0) strength is highly fragmented and spread out over the energy region investigated. Microscopic continuum RPA calculations including the coupling of the basic particle-hole states to the low-lying surface vibrations are capable of reproducing the strength distributions quite accurately. Exhaustion of the energy-weighted sum rules (EWSR) for the various decay channels is presented. A complete decomposition of E0, E1 and E2 contributions in 40 Ca is possible for (e,e'α) angular correlations populating the 36 Ar ground state. Contrary to expectations, the form factors of isoscalar E0 and E2 strengths in the 40 Ca(e,e'α 0 ) reaction exhibit increasing differences towards smaller momentum transfers. Angular correlations for proton decay into low-lying states of 39 K are compared to a self-consistent continuum RPA calculation which allows a systematic description of the strong variations observed as a function of 40 Ca excitation energy and momentum transfer. The success implies that direct knock-out models of the 40 Ca(e,e'p) reaction are too simple. Furthermore, the shapes of the angular correlations seem to be determined largely by the final-state interaction, in particular by charge exchange reactions in the nuclear medium

  10. Resonance

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2014-01-01

    A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....

  11. Determination of the electromagnetic dipole strength distribution in medium-heavy atomic nuclei by means of nuclear resonance fluorescence; Bestimmung der elektromagnetischen Dipolstaerkeverteilung in mittelschweren Atomkernen mittels Kernresonanzfluoreszenz

    Energy Technology Data Exchange (ETDEWEB)

    Massarczyk, Ralph Jens

    2011-01-17

    During the last hundred years several models were developed to describe the configuration of nuclei. These models have to make predictions, which should be comparable with experiments. As a standard type of experiment the nuclear resonance fluorescence was established. A nucleus is excited by irradiation with photons. By emitting one or more photons the nucleus decays back to the ground state. With this method it is possible to measure energy levels and to determine the strength of their excitation. A continuum of unresolved peaks gives additional strength. The existing setup at the linear electron accelerator ELBE of the Forschungszentrum Dresden-Rossendorf uses bremsstrahlung, produced as a secondary beam in a thin Niobium foil. During the years 2008/09 experiments on the nuclei of {sup 86}Kr and {sup 136}Ba took place there. In this work they will be analyzed. Photon flux and efficiency determination have been done as well as simulations on detector response and non-nuclear scattered background events. For this purpose the GEANT4 package was used. Finally the resulting cross sections were corrected for branching and feeding.

  12. Giant cystic craniopharyngiomas

    International Nuclear Information System (INIS)

    Young, S.C.; Zimmerman, R.A.; Nowell, M.A.; Bilaniuk, L.T.; Hackney, D.B.; Grossman, R.I.; Goldberg, H.I.

    1987-01-01

    Three cases of giant cystic craniopharyngiomas with large areas of extension beyond the suprasellar area are presented. The magnetic resonance (MR) appearance in one case is described. These giant tumors had large, multilobulated cysts that comprised the bulk of the tumors. In one case, there was an unusual extension of the large tumor cyst into the lateral ventricle. In two cases, the tumors extended to the level of the foramen magnum. On CT, the cyst contents of these two tumors were hyperdense and became hypodense postoperatively. All three tumors harbored calcifications in the form of clumps in the suprasellar region and rim calcifications around the cysts. None of the tumors exhibited contrast enhancement. A literature review of the radiographic features of craniopharyngiomas is discussed. (orig.)

  13. Electric dipole excitation of {sup 208}Pb by polarized electron impact

    Energy Technology Data Exchange (ETDEWEB)

    Jakubassa-Amundsen, D.H. [University of Munich, Mathematics Institute, Munich (Germany); Ponomarev, V.Yu. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany)

    2016-03-15

    The cross sections and spin asymmetries for the excitation of 1{sup -} states in {sup 208}Pb by transversely polarized electrons with collision energy of 30-180MeV have been examined within the DWBA scattering formalism. As examples, we have considered a low-lying 1{sup -} state and also states belonging to the pygmy dipole and giant dipole resonances. The structure of these states and their corresponding transition charge and current densities have been taken from an RPA calculation within the quasiparticle phonon model. The complex-plane rotation method has been applied to achieve the convergence of the radial DWBA integrals for backward scattering. We have studied the behaviour of the cross sections and spin asymmetries as a function of electron energy and scattering angle. The role of the longitudinal and transversal contributions to the excitation has been thoroughly studied. We conclude that the spin asymmetry S, related to unpolarized outgoing electrons, is mostly well below 1% even at the backward scattering angles and its measurement provides a challenge for future experiments with polarized electrons. (orig.)

  14. Dynamics of nonstationary dipole vortices

    DEFF Research Database (Denmark)

    Hesthaven, J.S.; Lynov, Jens-Peter; Nycander, J.

    1993-01-01

    The dynamics of tilted dipole vortices in the equivalent barotropic vorticity (or Hasegawa-Mima) equation is studied. A recent theory is compared with numerical simulations and found to describe the short time behavior of dipole vortices well. In the long time limit the dipoles are found to eithe...... disintegrate or relax toward a steady eastward propagating dipole vortex. This relaxation is a consequence of nonviscous enstrophy loss by the dipole vortex....

  15. Non-foster impedance matching sensitivity of electrically small electric and magnetic spherical dipole antennas

    DEFF Research Database (Denmark)

    Yoon, Ick-Jae; Christensen, S.; Zhurbenko, Vitaliy

    2016-01-01

    The impedance bandwidth (BW) improvement property of a self-resonant folded spherical helix electric dipole and a spherical split ring (SSR) magnetic dipole is compared when a negative reactance element is loaded on the parasitic resonator of the antennas. They have the same electrical size of ka...

  16. Giant Chancroid

    Directory of Open Access Journals (Sweden)

    Bhushan Kumar

    1980-01-01

    Full Text Available A case of giant chancroid following rupture of inguinal bubo and having systemic symptoms is described. Response with sulfa and streptomycin combination was excellent and the lesion healed completely in 3 weeks. Early diagnosis and treatment of chancroid will prevent this debilitating complication.

  17. Giant microelectronics

    International Nuclear Information System (INIS)

    Della Sala, D.; Privato, C.; Di Lazzaro, P.; Fortunato, G.

    1999-01-01

    Giant microelectronics, on which the technology of flat liquid-crystal screens is based, is an example of fruitful interaction among independently-developed technologies, in this case thin film micro devices and laser applications. It typifies the interdisciplinary approach needed to produce innovations in microelectronics [it

  18. Resonances in odd-odd 182Ta

    Science.gov (United States)

    Brits, C. P.; Wiedeking, M.; Bello Garrote, F. L.; Bleuel, D. L.; Giacoppo, F.; Görgen, A.; Guttormsen, M.; Hadynska-Klek, K.; Hagen, T. W.; Ingeberg, V. W.; Kheswa, B. V.; Klintefjord, M.; Larsen, A. C.; Malatji, K. L.; Nyhus, H. T.; Papka, P.; Renstrøm, T.; Rose, S.; Sahin, E.; Siem, S.; Tveten, G. M.; Zeiser, F.

    2017-09-01

    Enhanced γ-decay on the tail of the giant electric dipole resonance, such as the scissors or pygmy resonances, can have significant impact on (n,γ) reaction rates. These rates are important input for modeling processes that take place in astrophysical environments and nuclear reactors. Recent results from the University of Oslo indicate the existence of a significant enhancement in the photon strength function for nuclei in the actinide region due to the scissors resonance. Further, the M1 strength distribution of the scissors resonances in rare earth nuclei has been studied extensively over the years. To investigate the evolution and persistence of the scissor resonance in other mass regions, an experiment was performed utilizing the NaI(Tl) γ-ray detector array (CACTUS) and silicon particle telescopes (SiRi) at the University of Oslo Cyclotron laboratory. Particle-γ coincidences from the 181Ta(d,p)182Ta and 181Ta(d,d')181Ta reactions were used to measure the nuclear level density and photon strength function of the well-deformed 181Ta and 182Ta systems, to investigate the existence of resonances below the neutron separation energy. Note to the reader: the title of this article has been corrected on September 19, 2017.

  19. Resonances in odd-odd 182Ta

    Directory of Open Access Journals (Sweden)

    Brits C.P.

    2017-01-01

    Full Text Available Enhanced γ-decay on the tail of the giant electric dipole resonance, such as the scissors or pygmy resonances, can have significant impact on (n,γ reaction rates. These rates are important input for modeling processes that take place in astrophysical environments and nuclear reactors. Recent results from the University of Oslo indicate the existence of a significant enhancement in the photon strength function for nuclei in the actinide region due to the scissors resonance. Further, the M1 strength distribution of the scissors resonances in rare earth nuclei has been studied extensively over the years. To investigate the evolution and persistence of the scissor resonance in other mass regions, an experiment was performed utilizing the NaI(Tl γ-ray detector array (CACTUS and silicon particle telescopes (SiRi at the University of Oslo Cyclotron laboratory. Particle-γ coincidences from the 181Ta(d,p182Ta and 181Ta(d,d'181Ta reactions were used to measure the nuclear level density and photon strength function of the well-deformed 181Ta and 182Ta systems, to investigate the existence of resonances below the neutron separation energy.

  20. The LHC AC Dipole system: an introduction

    CERN Document Server

    Serrano, J; CERN. Geneva. BE Department

    2010-01-01

    The LHC AC Dipole is an instrument to study properties of the LHC lattice by inducing large transverse displacements in the beam. These displacements are generated by exciting the beam with an oscillating magnetic field at a frequency close to the tune. This paper presents the system requirements and the technical solution chosen to meet them, based of high-power audio amplifiers and a resonant parallel RLC circuit.

  1. Magnetic field modification of optical magnetic dipoles.

    Science.gov (United States)

    Armelles, Gaspar; Caballero, Blanca; Cebollada, Alfonso; Garcia-Martin, Antonio; Meneses-Rodríguez, David

    2015-03-11

    Acting on optical magnetic dipoles opens novel routes to govern light-matter interaction. We demonstrate magnetic field modification of the magnetic dipolar moment characteristic of resonant nanoholes in thin magnetoplasmonic films. This is experimentally shown through the demonstration of the magneto-optical analogue of Babinet's principle, where mirror imaged MO spectral dependencies are obtained for two complementary magnetoplasmonic systems: holes in a perforated metallic layer and a layer of disks on a substrate.

  2. (1) Majorana fermions in pinned vortices; (2) Manipulating and probing Majorana fermions using superconducting circuits; and (3) Controlling a nanowire spin-orbit qubit via electric-dipole spin resonance

    Science.gov (United States)

    Nori, Franco

    2014-03-01

    We study a heterostructure which consists of a topological insulator and a superconductor with a hole. This system supports a robust Majorana fermion state bound to the vortex core. We study the possibility of using scanning tunneling spectroscopy (i) to detect the Majorana fermion in this setup and (ii) to study excited states bound to the vortex core. The Majorana fermion manifests itself as an H-dependent zero-bias anomaly of the tunneling conductance. The excited states spectrum differs from the spectrum of a typical Abrikosov vortex, providing additional indirect confirmation of the Majorana state observation. We also study how to manipulate and probe Majorana fermions using super-conducting circuits. In we consider a semiconductor nanowire quantum dot with strong spin-orbit coupling (SOC), which can be used to achieve a spin-orbit qubit. In contrast to a spin qubit, the spin-orbit qubit can respond to an external ac electric field, i.e., electric-dipole spin resonance. We develop a theory that can apply in the strong SOC regime. We find that there is an optimal SOC strength ηopt = √ 2/2, where the Rabi frequency induced by the ac electric field becomes maximal. Also, we show that both the level spacing and the Rabi frequency of the spin-orbit qubit have periodic responses to the direction of the external static magnetic field. These responses can be used to determine the SOC in the nanowire. FN is partly supported by the RIKEN CEMS, iTHES Project, MURI Center for Dynamic Magneto-Optics, JSPS-RFBR Contract No. 12-02-92100, Grant-in-Aid for Scientific Research (S), MEXT Kakenhi on Quantum Cybernetics, and the JSPS via its FIRST program.

  3. Dipoles at rest

    International Nuclear Information System (INIS)

    Griffiths, D.J.

    1992-01-01

    In a world populated by magnetic monopoles (as well as ordinary electric charges), there are two kinds of electric dipoles: those due to separated electric charges, and those due to current loops of magnetic charge. Similarly, there are two kinds of magnetic dipoles: those due to separated magnetic monopoles, and those due to electric current loops. This paper derives the potentials and fields of each of the four dipole species, and calculates the force, torque, energy, momentum, and angular momentum of each type, when placed (at rest) in a static external field (which may itself be produced by electric charges and currents, magnetic charges and currents, or all of these). Some implications and applications of the various results are discussed

  4. Automating dipole subtraction

    International Nuclear Information System (INIS)

    Hasegawa, K.; Moch, S.; Uwer, P.

    2008-07-01

    We report on automating the Catani-Seymour dipole subtraction which is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. The automatization rests on three essential steps: the creation of the dipole terms, the calculation of the color linked squared Born matrix elements, and the evaluation of different helicity amplitudes. The routines have been tested for a number of complex processes, such as the real emission process gg→t anti tggg. (orig.)

  5. Automating dipole subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, K.; Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Uwer, P. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Theoretische Teilchenphysik

    2008-07-15

    We report on automating the Catani-Seymour dipole subtraction which is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. The automatization rests on three essential steps: the creation of the dipole terms, the calculation of the color linked squared Born matrix elements, and the evaluation of different helicity amplitudes. The routines have been tested for a number of complex processes, such as the real emission process gg{yields}t anti tggg. (orig.)

  6. Automatic dipole subtraction

    International Nuclear Information System (INIS)

    Hasegawa, K.

    2008-01-01

    The Catani-Seymour dipole subtraction is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. We automatized the procedure in a computer code. The code is useful especially for the processes with many parton legs. In this talk, we first explain the algorithm of the dipole subtraction and the whole structure of our code. After that we show the results for some processes where the infrared divergences of real emission processes are subtracted. (author)

  7. Dipole-dipole van der Waals interaction in alkali halides

    International Nuclear Information System (INIS)

    Thakur, B.N.; Thakur, K.P.

    1978-01-01

    Values of van der Waals dipole-dipole constants and interaction energetics of alkali halides are reported using the recent data. The values obtained are somewhat larger than those of earlier workers. (orig.) [de

  8. Measurements of ground motion and SSC dipole vibrations

    International Nuclear Information System (INIS)

    Parkhomchuk, V.V.; Shiltsev, V.D.; Weaver, H.J.

    1993-06-01

    The results of seismic ground measurements at the Superconducting Super Collider (SSC) site and investigations of vibrational properties of superconducting dipoles for the SSC are presented. Spectral analysis of the data obtained in the large frequency band from 0.05 Hz to 2000 Hz is done. Resonant behavior and the dipole-to-ground transform ratio are investigated. The influence of measured vibrations on SSC operations is considered

  9. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...

  10. Beam Manipulation with an RF Dipole

    International Nuclear Information System (INIS)

    Bai, M.

    1999-01-01

    Coherent betatron motion adiabatically excited by an RF dipole has been successfully employed to overcome strong intrinsic spin depolarization resonances in the AGS, while a solenoid partial snake has been used to correct imperfection spin resonances. The experimental results showed that a full spin flip was obtained in passing through an intrinsic spin resonance when all the beam particles were forced to oscillate coherently at a large amplitude without diluting the beam emittance. With this method, they have successfully accelerated polarized beam up to 23.5 GeV/c. A new type of second order spin resonances was also discovered. As a non-destructive manipulation, this method can also be used for nonlinear beam dynamics studies and beam diagnosis such as measuring phase advance and betatron amplitude function

  11. Dipole-dipole interaction of dust grains in plasmas

    International Nuclear Information System (INIS)

    Tskhakaya, D.D.; Shukla, P.K.

    2005-01-01

    Complete screening of the negative dust grain charge by a cloud of trapped ions in plasmas is investigated. In the external electric field, the compound dust particle - 'dust grain + ion cloud' acquires a dipole moment due to displacement of the centers of positive and negative charges in the opposite directions. By analogy to the Van der Waals potential, the dipole-dipole interaction of the compound dust particles can have an attractive behavior. It is shown that the dipole-dipole attractive force can exceed the shadowing force that is connected with the reciprocal interception of ions by the neighboring dust grains

  12. RCNP E398 {sup 16}O,{sup 12}C(p,p’) experiment: Measurement of the γ-ray emission probability from giant resonances in relation to {sup 16}O,{sup 12}C(ν,ν’) reactions

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Effect translational invariance in low-lying electric dipole excitations in 236U and 238U

    International Nuclear Information System (INIS)

    Ertugral, F.

    2005-01-01

    In this paper the translational invariant QRPA approach suggested by Pyatov [1] for the spherical nuclei has been extended to describe the 1 - states in deformed nuclei. The role of spurious centre-of-motion state on the Pygmy dipole resonance (PDR) has been investigated in the deformed 236 U and 238 U nuclei. It has been shown that the effect of taking into account the translational invariance of the Hamiltonians in the QRPA with separation of zero energy spurious solutions are noticeable in both the low energy density of 1 - states and in the PDR. Present investigation demonstrates the advantage of the translational invariant QRPA over the non translational invariant one. Within the translational invariant model the effect of removing spurious states on the E1 strength distribution is stronger than in none invariant QRPA (∼20%) for the states up to the neutron binding energy. It is found that the spurious state is spread over many levels, the largest admixture being situated in the region of the energy spacing between nuclear shells o w h . The giant resonance states contain, as a rule, very small admixtures of the spurious state

  14. Sensitivity of nonlinear photoionization to resonance substructure in collective excitation

    Science.gov (United States)

    Mazza, T.; Karamatskou, A.; Ilchen, M.; Bakhtiarzadeh, S.; Rafipoor, A. J.; O'Keeffe, P.; Kelly, T. J.; Walsh, N.; Costello, J. T.; Meyer, M.; Santra, R.

    2015-01-01

    Collective behaviour is a characteristic feature in many-body systems, important for developments in fields such as magnetism, superconductivity, photonics and electronics. Recently, there has been increasing interest in the optically nonlinear response of collective excitations. Here we demonstrate how the nonlinear interaction of a many-body system with intense XUV radiation can be used as an effective probe for characterizing otherwise unresolved features of its collective response. Resonant photoionization of atomic xenon was chosen as a case study. The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance. Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources. PMID:25854939

  15. Dissecting an LHC dipole

    CERN Multimedia

    2004-01-01

    The cold mass of a 15-metre main dipole magnet has some fifteen different components. All the main components are manufactured under CERN's direct responsibility. Four of them transit through CERN before being shipped to the dipole assembly contractors, namely the cable, which constitutes the magnet's superconducting core (see Bulletin 14/2004), the beam screens, the heat exchanger tubes and the cold bore beam tubes. The two latter components transit via Building 927 where they undergo part of the production process. The 58-mm diameter heat exchanger tubes will remove heat from the magnets using superfluid helium. The 53-mm diameter cold bore tubes will be placed under vacuum to allow the twin beams to circulate around the LHC.

  16. Low-Q Electrically Small Spherical Magnetic Dipole Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2010-01-01

    Three novel electrically small antenna configurations radiating a TE10 spherical mode corresponding to a magnetic dipole are presented and investigated: multiarm spherical helix (MSH) antenna, spherical split ring resonator (S-SRR) antenna, and spherical split ring (SSR) antenna. All three antennas...... are self-resonant, with the input resistance tuned to 50 ohms by an excitation curved dipole/monopole. A prototype of the SSR antenna has been fabricated and measured, yielding results that are consistent with the numerical simulations. Radiation quality factors (Q) of these electrically small antennas (in...

  17. Experiments with dipole antennas

    International Nuclear Information System (INIS)

    Kraftmakher, Yaakov

    2009-01-01

    Employment of a data-acquisition system for data collection and calculations makes experiments with antennas more convenient and less time consuming. The determined directional patterns of the dipole antennas of different lengths are in reasonable agreement with theory. The enhancement of the signal by using a reflector is demonstrated, and a variant of the Yagi-Uda antenna is explored. The experiments are suitable as laboratory works and classroom demonstrations, and are attractive for student projects.

  18. ALICE dipole and decoration

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    The ALICE cavern receives a painting made specially to mark the 50th anniversary of CERN that is mounted on the L3 solenoid magnet, reused from the LEP experiment that ran from 1989 to 2000. The dipole, which is cooled by demineralised water, will bend the path of muons that leave the huge rectangular solenoid. These muons are heavy electrons that interact less with matter allowing them to be studied at large distances from the interaction point.

  19. Visualizing dipole radiation

    International Nuclear Information System (INIS)

    Girwidz, Raimund V

    2016-01-01

    The Hertzian dipole is fundamental to the understanding of dipole radiation. It provides basic insights into the genesis of electromagnetic waves and lays the groundwork for an understanding of half-wave antennae and other types. Equations for the electric and magnetic fields of such a dipole can be derived mathematically. However these are very abstract descriptions. Interpreting these equations and understanding travelling electromagnetic waves are highly limited in that sense. Visualizations can be a valuable supplement that vividly present properties of electromagnetic fields and their propagation. The computer simulation presented below provides additional instructive illustrations for university lectures on electrodynamics, broadening the experience well beyond what is possible with abstract equations. This paper refers to a multimedia program for PCs, tablets and smartphones, and introduces and discusses several animated illustrations. Special features of multiple representations and combined illustrations will be used to provide insight into spatial and temporal characteristics of field distributions—which also draw attention to the flow of energy. These visualizations offer additional information, including the relationships between different representations that promote deeper understanding. Finally, some aspects are also illustrated that often remain unclear in lectures. (paper)

  20. Dipole defects in beryl

    International Nuclear Information System (INIS)

    Holanda, B A; Cordeiro, R C; Blak, A R

    2010-01-01

    Dipole defects in gamma irradiated and thermally treated beryl (Be 3 Al 2 Si 6 O 18 ) samples have been studied using the Thermally Stimulated Depolarization Currents (TSDC) technique. TSDC experiments were performed in pink (morganite), green (emerald), blue (aquamarine) and colourless (goshenite) natural beryl. TSDC spectra present dipole peaks at 190K, 220K, 280K and 310K that change after gamma irradiation and thermal treatments. In morganite samples, for thermal treatments between 700K and 1100K, the 280K peak increase in intensity and the band at 220K disappears. An increase of the 280K peak and a decrease of the 190K peak were observed in the TSDC spectra of morganite after a gamma irradiation of 25kGy performed after the thermal treatments. In the case of emerald samples, thermal treatments enhanced the 280K peak and gamma irradiation partially destroyed this band. The goshenite TSDC spectra present only one band at 280K that is not affected either by thermal treatments or by gamma irradiation. All the observed peaks are of dipolar origin because the intensity of the bands is linearly dependent on the polarization field, behaviour of dipole defects. The systematic study, by means of TSDC measurements, of ionizing irradiation effects and thermal treatments in these crystals makes possible a better understanding of the role played by the impurities in beryl crystals.

  1. Dipole response of 76Se above 4 MeV

    Science.gov (United States)

    Goddard, P. M.; Cooper, N.; Werner, V.; Rusev, G.; Stevenson, P. D.; Rios, A.; Bernards, C.; Chakraborty, A.; Crider, B. P.; Glorius, J.; Ilieva, R. S.; Kelley, J. H.; Kwan, E.; Peters, E. E.; Pietralla, N.; Raut, R.; Romig, C.; Savran, D.; Schnorrenberger, L.; Smith, M. K.; Sonnabend, K.; Tonchev, A. P.; Tornow, W.; Yates, S. W.

    2013-12-01

    The dipole response of 3476Se in the energy range from 4 to 9 MeV has been analyzed using a (γ⃗,γ') polarized photon scattering technique, performed at the High Intensity γ-Ray Source facility at Triangle Universities Nuclear Laboratory, to complement previous work performed using unpolarized photons. The results of this work offer both an enhanced sensitivity scan of the dipole response and an unambiguous determination of the parities of the observed J=1 states. The dipole response is found to be dominated by E1 excitations, and can reasonably be attributed to a pygmy dipole resonance. Evidence is presented to suggest that a significant amount of directly unobserved excitation strength is present in the region, due to unobserved branching transitions in the decays of resonantly excited states. The dipole response of the region is underestimated when considering only ground state decay branches. We investigate the electric dipole response theoretically, performing calculations in a three-dimensional (3D) Cartesian-basis time-dependent Skyrme-Hartree-Fock framework.

  2. Effect of finite detection efficiency on the observation of the dipole-dipole interaction of a few Rydberg atoms

    International Nuclear Information System (INIS)

    Ryabtsev, I. I.; Tretyakov, D. B.; Beterov, I. I.; Entin, V. M.

    2007-01-01

    We have developed a simple analytical model describing multiatom signals that are measured in experiments on dipole-dipole interaction at resonant collisions of a few Rydberg atoms. It has been shown that finite efficiency of the selective field-ionization detector leads to the mixing up of the spectra of resonant collisions registered for various numbers of Rydberg atoms. The formulas which help to estimate an appropriate mean Rydberg atom number for a given detection efficiency are presented. We have found that a measurement of the relation between the amplitudes of collisional resonances observed in the one- and two-atom signals provides a straightforward determination of the absolute detection efficiency and mean Rydberg atom number. We also performed a testing experiment on resonant collisions in a small excitation volume of a sodium atomic beam. The resonances observed for 1-4 detected Rydberg atoms have been analyzed and compared with theory

  3. Destructive interference between electric and toroidal dipole moments in TiO2 cylinders and frustums with coaxial voids

    Science.gov (United States)

    Terekhov, P. D.; Baryshnikova, K. V.; Evlyukhin, A. B.; Shalin, A. S.

    2017-11-01

    We demonstrate numerically the possibility of multipole interference in the TiO2 (titanium dioxide) microcylinders and microfrustums in the wavelength range 210-300 μm. Resonantly strong destructive interference between toroidal and electric dipole contributions to the scattered field is achieved by a geometry tuning. The toroidal and electric dipole mode overlapping at the resonant wavelength with almost total suppression of the total electric dipole moment is achieved.

  4. AutoDipole - Automated generation of dipole subtraction terms

    International Nuclear Information System (INIS)

    Hasegawa, K.; Uwer, P.

    2009-11-01

    We present an automated generation of the subtraction terms for next-to-leading order QCD calculations in the Catani-Seymour dipole formalism. For a given scattering process with n external particles our Mathematica package generates all dipole terms, allowing for bothmassless and massive dipoles. The numerical evaluation of the subtraction terms proceeds with MadGraph, which provides Fortran code for the necessary scattering amplitudes. Checks of the numerical stability are discussed. (orig.)

  5. AutoDipole - Automated generation of dipole subtraction terms

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, K.; Uwer, P. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2009-11-15

    We present an automated generation of the subtraction terms for next-to-leading order QCD calculations in the Catani-Seymour dipole formalism. For a given scattering process with n external particles our Mathematica package generates all dipole terms, allowing for bothmassless and massive dipoles. The numerical evaluation of the subtraction terms proceeds with MadGraph, which provides Fortran code for the necessary scattering amplitudes. Checks of the numerical stability are discussed. (orig.)

  6. Observation of low-lying resonances in the quasicontinuum of 195,196Pt and enhanced astrophysical reaction rates

    Directory of Open Access Journals (Sweden)

    Giacoppo F.

    2015-01-01

    Full Text Available An excess of strength on the low-energy tail of the giant dipole resonance recently has been observed in the γ-decay from the quasicontinuum of 195,196Pt. The nature of this phenomenon is not yet fully investigated. If this feature is present also in the γ-ray strength of the neutron-rich isotopes, it can affect the neutron-capture reactions involved in the formation of heavy-elements in stellar nucleosynthesis. The experimental level density and γ-ray strength function of 195,196Pt are presented together with preliminary calculations of the corresponding neutron-capture cross sections.

  7. Neutron Electric Dipole Moment

    International Nuclear Information System (INIS)

    Mischke, R.E.

    2003-01-01

    The status of experiments to measure the electric dipole moment of the neutron is presented and the planned experiment at Los Alamos is described. The goal of this experiment is an improvement in sensitivity of a factor of 50 to 100 over the current limit. It has the potential to reveal new sources of T and CP violation and to challenge calculations that propose extensions to the Standard Model. The experiment employs several advances in technique to reach its goals and the feasibility of meeting these technical challenges is currently under study

  8. Complete dipole response in 208Pb from high-resolution polarized proton scattering at 0 deg

    International Nuclear Information System (INIS)

    Neumann-Cosel, P. von; Kalmykov, Y.; Poltoratska, I.; Ponomarev, V. Yu.; Richter, A.; Wambach, J.; Adachi, T.; Fujita, Y.; Matsubara, H.; Sakemi, Y.; Shimizu, Y.; Tameshige, Y.; Yosoi, M.; Bertulani, C. A.; Carter, J.; Fujita, H.; Dozono, M.; Fujita, K.; Hashimoto, H.; Hatanaka, K.

    2009-01-01

    The structure of electric and magnetic dipole modes in 208 Pb is investigated in a high-resolution measurement of the (p-vector,p-vector') reaction under 0 deg. First results on the E1 strength in the region of the pygmy dipole resonance are reported.

  9. Giant arachnoid granulation in a patient with benign intracranial hypertension

    International Nuclear Information System (INIS)

    Kiroglu, Yilmaz; Yaqci, Baki; Cirak, Bayram; Karabulut, Nevzat

    2008-01-01

    We report magnetic resonance (MR), computed tomography (CT) and angiographic imaging of an unusual giant arachnoid granulation in the superior sagittal sinus in a man with headache and vertigo. Intrasinus pressure measurements revealed a significant pressure gradient across the lesion. MR imaging is useful to identify giant arachnoid granulation and dural sinus thrombosis, whereas dural sinus pressure measurement in certain cases of giant arachnoid granulations can be used to evaluate the lesion as the cause of the patient's symptoms. (orig.)

  10. Giant arachnoid granulation in a patient with benign intracranial hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Kiroglu, Yilmaz; Yaqci, Baki; Cirak, Bayram; Karabulut, Nevzat [Pamukkale University, Department of Radiology, School of Medicine, Denizli (Turkey)

    2008-10-15

    We report magnetic resonance (MR), computed tomography (CT) and angiographic imaging of an unusual giant arachnoid granulation in the superior sagittal sinus in a man with headache and vertigo. Intrasinus pressure measurements revealed a significant pressure gradient across the lesion. MR imaging is useful to identify giant arachnoid granulation and dural sinus thrombosis, whereas dural sinus pressure measurement in certain cases of giant arachnoid granulations can be used to evaluate the lesion as the cause of the patient's symptoms. (orig.)

  11. Measurement of Gamow-Teller and spin dipole strength in the 45Sc(n,p)45Ca reaction at 198 MeV

    International Nuclear Information System (INIS)

    Alford, W.P.; Celler, A.; Brown, B.A.; Long, S.; Raywood, K.

    1990-11-01

    The reaction 45 Sc(n,p) 45 Ca has been studied at an energy of 198 MeV with energy resolution of about 1 MeV. Measurements were carried out at nominal angles 0, 3, 6, 9, 12, 15, and 18 degrees and spectra obtained up to ∼40 MeV excitation energy in 45 Ca. Significant Gamow-Teller strength is observed at an excitation energy of about 7 MeV, somewhat higher than predicted by shell model calculations. The strength observed is in agreement with calculations using g A /g V ≅ 1. The spin dipole giant resonance is seen with centroid at about 15 MeV excitation and total cross section of 25 mb/sr at an angle of 6 degrees. (Author) (22 refs., 9 figs.)

  12. Magnetic dipole moment of a moving electric dipole

    OpenAIRE

    Hnizdo, V.

    2012-01-01

    The current density of a moving electric dipole is expressed as the sum of polarization and magnetization currents. The magnetic field due to the latter current is that of a magnetic dipole moment that is consistent with the relativistic transformations of the polarization and magnetization of macroscopic electrodynamics.

  13. Collisional transfer of coherence by electric dipole-dipole interaction

    OpenAIRE

    Gough , W.

    1983-01-01

    An expression is derived for the contribution from dipole-dipole interaction to the intensity of sensitized fluorescence, from the results of a theory by Chiu. Tensor operator methods are used. The degree of polarization is deduced for certain particular cases.

  14. SPS Dipole Multipactor Test and TEWave Diagnostics

    CERN Document Server

    Caspers, F; Edwards, P; Federmann, S; Holz, M; Taborelli, M

    2013-01-01

    Electron cloud accumulation in particle accelerators can be mitigated by coating the vacuum beam pipe with thin films of low secondary electron yield (SEY) material. The SEY of small coated samples are usually measured in the laboratory. To further test the properties of different coating materials, RF-induced multipacting in a coaxial waveguide configuration can be performed. The technique is applied to two main bending dipoles of the SPS, where the RF power is fed through a tungsten wire stretched along the vacuum chamber (6.4 m). A dipole with a bare stainless steel chamber shows a clear power threshold initiating an abrupt rise in reflected power and pressure. The effect is enhanced at RF frequencies corresponding to electron cyclotron resonances for given magnetic fields. Preliminary results show that the dipole with a carbon coated vacuum chamber does not exhibit any pressure rise or reflected RF power up to the maximum available input power. In the case of a large scale coating production this techniqu...

  15. Magnetic field of a dipole and the dipole-dipole interaction

    International Nuclear Information System (INIS)

    Kraftmakher, Yaakov

    2007-01-01

    With a data-acquisition system and sensors commercially available, it is easy to determine magnetic fields produced by permanent magnets and to study the dipole-dipole interaction for different separations and angular positions of the magnets. For sufficiently large distances, the results confirm the 1/R 3 law for the magnetic field and the 1/R 4 law for the interaction force between two dipoles, as well as their angular dependences

  16. Coherent and incoherent giant dipole resonance γ-ray emission induced by heavy ion collisions: Study of the 40Ca+48Ca system by means of the constrained molecular dynamics model

    International Nuclear Information System (INIS)

    Papa, Massimo; Cardella, Giuseppe; Bonanno, Antonio; Pappalardo, Giuseppe; Rizzo, Francesca; Amorini, Francesca; Bonasera, Aldo; Di Pietro, Alessia; Figuera, Pier Paolo; Tudisco, Salvatore; Maruyama, Toshiki

    2003-01-01

    Coherent and incoherent dipolar γ-ray emission is studied in a fully dynamical approach by means of the constrained molecular dynamics model. The study is focused on the system 40 Ca+ 48 Ca for which recently experimental data have been collected at 25 MeV/nucleon. The approach allows us to explain the experimental results in a self-consistent way without using statistical or hybrid models. Moreover, calculations performed at higher energy show interesting correlations between the fragment formation process, the degree of collectivity, and the coherence degree of the γ-ray emission process

  17. Investigation of the dipole response of nickel isotopes in the presence of a high-frequency electromagnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Dominic M.

    2010-01-25

    The electric dipole response of neutron-rich nickel isotopes has been investigated using the LAND setup at GSI in Darmstadt (Germany). Relativistic secondary beams of {sup 56-57}Ni and {sup 67-72}Ni at approximately 500 AMeV have been generated using projectile fragmentation of stable ions on a 4 g/cm{sup 2} Be target and subsequent separation in the magnetic dipole fields of the FRagment Separator (FRS). After reaching the LAND setup in Cave C, the radioactive ions were excited electromagnetically in the electric field of a Pb target. The decay products have been measured in inverse kinematics using various detectors. Neutron-rich {sup 67-69}Ni isotopes decay by the emission of neutrons, which are detected in the LAND detector. The present analysis concentrates on the ({gamma},n) and ({gamma},2n) channels in these nuclei, since the proton and three-neutron thresholds are unlikely to be reached considering the virtual photon spectrum for nickel ions at 500 AMeV. A measurement of the stable {sup 58}Ni isotope is used as a benchmark to check the accuracy of the present results with previously published data. The measured ({gamma},n) and ({gamma},np) channels are compared with an inclusive photoneutron measurement by Fultz and coworkers, which are consistent within the respective errors. The measured excitation energy distributions of {sup 67-69}Ni contain a large portion of the Giant Dipole Resonance (GDR) strength predicted by the Thomas-Reiche-Kuhn energy-weighted sum rule, as well as a significant amount of low-lying E1 strength, that cannot be attributed to the GDR alone. The GDR distribution parameters are calculated using well-established semi-empirical systematic models, providing the peak energies and widths. The GDR strength is extracted from the {chi}{sup 2} minimization of the model GDR to the measured data of the ({gamma},2n) channel, thereby excluding any influence of eventual low-lying strength. The subtraction of the obtained GDR distribution from the

  18. Backfire antennas with dipole elements

    DEFF Research Database (Denmark)

    Nielsen, Erik Dragø; Pontoppidan, Knud

    1970-01-01

    A method is set up for a theoretical investigation of arbitrary backfire antennas based upon dipole structures. The mutual impedance between the dipole elements of the antenna is taken into account, and the field radiated due to a surface wave reflector of finite extent is determined by calculating...

  19. Dipole plasma in molecular crystals

    International Nuclear Information System (INIS)

    Kotel'nikov, Yu.E.; Kochelaev, B.I.

    1976-01-01

    Collective oscillations in a system of electric dipoles of molecular crystals are investigated. It has been proved in the exciton approximation that in an elementary cell of a molecular crystal with one molecule there may exist energy fluctuations of the ''dipole'' plasma, analogous to plasma oscillations in the charged Fermi liquid

  20. Neutron Electric Dipole Moment Experiments

    OpenAIRE

    Peng, Jen-Chieh

    2008-01-01

    The neutron electric dipole moment (EDM) provides unique information on CP violation and physics beyond the Standard Model. We first review the history of experimental searches for neutron electric dipole moment. The status of future neutron EDM experiments, including experiments using ultra-cold neutrons produced in superfluid helium, will then be presented.

  1. Mapping the HISS Dipole

    International Nuclear Information System (INIS)

    McParland, C.; Bieser, F.

    1984-01-01

    The principal component of the Bevalac HISS facility is a large super-conducting 3 Tesla dipole. The facility's need for a large magnetic volume spectrometer resulted in a large gap geometry - a 2 meter pole tip diameter and a 1 meter pole gap. Obviously, the field required detailed mapping for effective use as a spectrometer. The mapping device was designed with several major features in mind. The device would measure field values on a grid which described a closed rectangular solid. The grid would be a regular with the exact measurement intervals adjustable by software. The device would function unattended over the long period of time required to complete a field map. During this time, the progress of the map could be monitored by anyone with access to the HISS VAX computer. Details of the mechanical, electrical, and control design follow

  2. Pressure profiles of plasmas confined in the field of a magnetic dipole

    International Nuclear Information System (INIS)

    Davis, Matthew S; Mauel, M E; Garnier, Darren T; Kesner, Jay

    2014-01-01

    Equilibrium pressure profiles of plasmas confined in the field of a dipole magnet are reconstructed using magnetic and x-ray measurements on the levitated dipole experiment (LDX). LDX operates in two distinct modes: with the dipole mechanically supported and with the dipole magnetically levitated. When the dipole is mechanically supported, thermal particles are lost along the field to the supports, and the plasma pressure is highly peaked and consists of energetic, mirror-trapped electrons that are created by electron cyclotron resonance heating. By contrast, when the dipole is magnetically levitated losses to the supports are eliminated and particles are lost via slower cross-field transport that results in broader, but still peaked, plasma pressure profiles. (paper)

  3. Transforming giants.

    Science.gov (United States)

    Kanter, Rosabeth Moss

    2008-01-01

    Large corporations have long been seen as lumbering, inflexible, bureaucratic--and clueless about global developments. But recently some multinationals seem to be transforming themselves: They're engaging employees, moving quickly, and introducing innovations that show true connection with the world. Harvard Business School's Kanter ventured with a research team inside a dozen global giants--including IBM, Procter & Gamble, Omron, CEMEX, Cisco, and Banco Real--to discover what has been driving the change. After conducting more than 350 interviews on five continents, she and her colleagues came away with a strong sense that we are witnessing the dawn of a new model of corporate power: The coordination of actions and decisions on the front lines now appears to stem from widely shared values and a sturdy platform of common processes and technology, not from top-down decrees. In particular, the values that engage the passions of far-flung workforces stress openness, inclusion, and making the world a better place. Through this shift in what might be called their guidance systems, the companies have become as creative and nimble as much smaller ones, even while taking on social and environmental challenges of a scale that only large enterprises could attempt. IBM, for instance, has created a nonprofit partnership, World Community Grid, through which any organization or individual can donate unused computing power to research projects and see what is being done with the donation in real time. IBM has gained an inspiring showcase for its new technology, helped business partners connect with the company in a positive way, and offered individuals all over the globe the chance to contribute to something big.

  4. YOUNG SOLAR SYSTEM's FIFTH GIANT PLANET?

    International Nuclear Information System (INIS)

    Nesvorný, David

    2011-01-01

    Studies of solar system formation suggest that the solar system's giant planets formed and migrated in the protoplanetary disk to reach the resonant orbits with all planets inside ∼15 AU from the Sun. After the gas disk's dispersal, Uranus and Neptune were likely scattered by the gas giants, and approached their current orbits while dispersing the transplanetary disk of planetesimals, whose remains survived to this time in the region known as the Kuiper Belt. Here we performed N-body integrations of the scattering phase between giant planets in an attempt to determine which initial states are plausible. We found that the dynamical simulations starting with a resonant system of four giant planets have a low success rate in matching the present orbits of giant planets and various other constraints (e.g., survival of the terrestrial planets). The dynamical evolution is typically too violent, if Jupiter and Saturn start in the 3:2 resonance, and leads to final systems with fewer than four planets. Several initial states stand out in that they show a relatively large likelihood of success in matching the constraints. Some of the statistically best results were obtained when assuming that the solar system initially had five giant planets and one ice giant, with the mass comparable to that of Uranus and Neptune, and which was ejected to interstellar space by Jupiter. This possibility appears to be conceivable in view of the recent discovery of a large number of free-floating planets in interstellar space, which indicates that planet ejection should be common.

  5. Young Solar System's Fifth Giant Planet?

    Science.gov (United States)

    Nesvorný, David

    2011-12-01

    Studies of solar system formation suggest that the solar system's giant planets formed and migrated in the protoplanetary disk to reach the resonant orbits with all planets inside ~15 AU from the Sun. After the gas disk's dispersal, Uranus and Neptune were likely scattered by the gas giants, and approached their current orbits while dispersing the transplanetary disk of planetesimals, whose remains survived to this time in the region known as the Kuiper Belt. Here we performed N-body integrations of the scattering phase between giant planets in an attempt to determine which initial states are plausible. We found that the dynamical simulations starting with a resonant system of four giant planets have a low success rate in matching the present orbits of giant planets and various other constraints (e.g., survival of the terrestrial planets). The dynamical evolution is typically too violent, if Jupiter and Saturn start in the 3:2 resonance, and leads to final systems with fewer than four planets. Several initial states stand out in that they show a relatively large likelihood of success in matching the constraints. Some of the statistically best results were obtained when assuming that the solar system initially had five giant planets and one ice giant, with the mass comparable to that of Uranus and Neptune, and which was ejected to interstellar space by Jupiter. This possibility appears to be conceivable in view of the recent discovery of a large number of free-floating planets in interstellar space, which indicates that planet ejection should be common.

  6. Modification of electric and magnetic dipole emission in anisotropic plasmonic systems.

    Science.gov (United States)

    Noginova, N; Hussain, R; Noginov, M A; Vella, J; Urbas, A

    2013-10-07

    In order to investigate the effects of plasmonic environments on spontaneous emission of magnetic and electric dipoles, we have studied luminescence of Eu³⁺ ions in close vicinity to gold nanostrip arrays. Significant changes in the emission kinetics, emission polarization, and radiation patterns have been observed in the wavelength range corresponding to the plasmonic resonance. The effect of the plasmonic resonance on the magnetic dipole transition ⁵D₀-->⁷F₁ is found to be very different from its effect on the electric dipole transitions. This makes Eu³⁺₋ containing complexes promising for mapping local distributions of magnetic and electric fields in metamaterials and plasmonic systems.

  7. Giant Cell Arteritis

    Science.gov (United States)

    Giant cell arteritis is a disorder that causes inflammation of your arteries, usually in the scalp, neck, and arms. ... arteries, which keeps blood from flowing well. Giant cell arteritis often occurs with another disorder called polymyalgia ...

  8. Study of the neutron decays of giant resonances excited by the inelastic scattering of 36 Ar on 90 Zr and 94 Zr targets at 44 MeV/u: a signature of multiphonon states

    International Nuclear Information System (INIS)

    Pascalon-Rozier, V.

    1997-01-01

    In inelastic heavy ion scattering, to angles near to the grazing angle, giant resonances (GR) are excited with very large differential cross sections. It has been shown that multiphonon states, states built with several GR quanta, can also been excited. These states can be revealed through the measurement of their decay by light particle emission. In this thesis, we report on the study of inelastic scattering of 36 Ar at 44 MeV/u on target of 90 Zr and 94 Zr, measured in coincidence with neutrons detected with the EDEN multidetector. The analysis of the inelastic spectra show evidence for a structure at high excitation energy, exhibiting characteristics compatible with a two-photon excitation. The construction of missing energy spectra allows us to the study of the GR and the high energy structure. In both nuclei, the GR presents a direct decay branch of 8%, which yields informations on the microscopic structure of the resonance. A two phonon state, interpreted as two weakly coupled GR's, built on one top of the other, and each phonon is expected to exhibit the same direct decay pattern as the GR. Such a simple decay is observed in the data, proving that the structure observed is due to the excitation of the two phonon state in both nuclei studied. Finally, we present a theoretical development based on Random Phase Approximation calculation, predicting that the two phonon state should be very harmonic. This result is in agreement with experimental studies of double phonon states over a large range of nuclei (from A = 12 to 208) carried out with several different probes. (author)

  9. Study of isovector resonances with pion charge exchange

    International Nuclear Information System (INIS)

    Baer, H.W.; Bolton, R.; Bowman, J.D.

    1982-01-01

    Studies with the pion charge exchange reactions (π/sup +-/,π 0 ) at 164 MeV using the LAMPF π 0 spectrometer are yielding new results on the existence and systematic features of isovector resonances in nuclei. These experiments possess an unusually high signal/background ratio for isovector resonances of low-multipolarity. Results obtained to date are: (1) observation and angular disribution measurement of the giant dipole resonance in nuclei 12 C, 40 Ca, 90 Zr, and 120 Sn; and (2) observation and angular distribution measurements in the (π - ,π 0 ) reaction on 90 Zr and 120 Sn of large signals possessing the expected angular distribution shapes and magnitudes for the isovector monopole resonance. Excitation energies are near the hydrodynamical model values 170 A - /sup 1/3/ MeV. Differential cross sections are approximately 0.7 J 1 2 (qR) mb/sr. An overview of this experimental program, with emphasis on new results and how they correlate with existing knowledge on the isovector resonances, is presented

  10. Spin and parity assignments to dipole excitations of the odd-mass nucleus {sup 207}Pb from nuclear resonance fluorescence experiments with linearly-polarized {gamma}-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Pietralla, N; Fritzsche, M; Savran, D [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Li, T C [Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Ahmed, M W; Tonchev, A P; Tornow, W; Weller, H R [Triangle Universities Nuclear Laboratory (TUNL), Duke University, Durham, NC 27708 (United States); Werner, V, E-mail: pietralla@ikp.tu-darmstadt.d [A.W. Wright Nuclear Structure Laboratory (WNSL), Yale University, New Haven, CT (United States)

    2010-01-01

    Pb({gamma}-vector ,{gamma}') photon scattering reactions were studied [1] with the nearly monochromatic, linearly polarized photon beams at the High Intensity {gamma}-ray Source (HI{gamma}S) at the DFELL. Azimuthal scattering intensity asymmetries measured with respect to the polarization plane of the beam have been used for the first time to assign both the spin and parity quantum numbers of dipole excited states of {sup 206,207,208}Pb at excitation energies in the vicinity of 5.5 MeV. Evidence for dominant particle-core coupling is deduced from these results along with information on excitation energies and electromagnetic transition matrix elements.

  11. LHC Dipoles Accelerate

    CERN Multimedia

    2001-01-01

    Andrezej Siemko (left), Peter Sievers (centre), and Lucio Rossi (right), have the exciting challenge of preparing and testing 2000 magnets for the LHC. The LHC is going to require a lot of powerful magnets by the time it begins operation in 2006. More specifically, it is going to need 130 special magnets, 400 quadrupoles, and a whopping 1250 dipoles! Preparing and testing these magnets for the conditions they will encounter in the LHC is not an easy task. But evaluation of the most recently received magnet, from the German company Noell, is showing that while the monumental task of receiving and testing nearly 2000 magnets is going to be exhausting, the goals are definitely attainable. At the moment and over the next year, pre-series magnets (the magnets that CERN uses to fine tune performance) are arriving slowly (90 in total will arrive), but by 2003 the rate of series magnet arrival will accelerate to 9 per week, that's over 450 in a single year! And working with these magnets when they arrive is tough. ...

  12. Tightly confined atoms in optical dipole traps

    International Nuclear Information System (INIS)

    Schulz, M.

    2002-12-01

    This thesis reports on the design and setup of a new atom trap apparatus, which is developed to confine few rubidium atoms in ultrahigh vacuum and make them available for controlled manipulations. To maintain low background pressure, atoms of a vapour cell are transferred into a cold atomic beam by laser cooling techniques, and accumulated by a magneto-optic trap (MOT) in a separate part of the vacuum system. The laser cooled atoms are then transferred into dipole traps made of focused far-off-resonant laser fields in single- or crossed-beam geometry, which are superimposed with the center of the MOT. Gaussian as well as hollow Laguerre-Gaussian (LG$ ( 01)$) beam profiles are used with red-detuned or blue-detuned light, respectively. Microfabricated dielectric phase objects allow efficient and robust mode conversion of Gaussian into Laguerre-Gaussian laser beams. Trap geometries can easily be changed due to the highly flexible experimental setup. The dipole trap laser beams are focused to below 10 microns at a power of several hundred milliwatts. Typical trap parameters, at a detuning of several ten nanometers from the atomic resonance, are trag depths of few millikelvin, trap frequencies near 30-kHz, trap light scattering rates of few hundred photons per atom and second, and lifetimes of several seconds. The number of dipole-trapped atoms ranges from more than ten thousand to below ten. The dipole-trapped atoms are detected either by a photon counting system with very efficient straylight discrimination, or by recapture into the MOT, which is imaged onto a sensitive photodiode and a CCD-camera. Due to the strong AC-Stark shift imposed by the high intensity trapping light, energy-selective resonant excitation and detection of the atoms is possible. The measured energy distribution is consistent with a harmonic potential shape and allows the determination of temperatures and heating rates. In first measurements, the thermal energy is found to be about 10 % of the

  13. Possible displacement of mercury's dipole

    International Nuclear Information System (INIS)

    Ng, K.H.; Beard, D.B.

    1979-01-01

    Earlier attempts to model the Hermean magnetospheric field based on a planet-centered magnetic multipole field have required the addition of a quadrupole moment to obtain a good fit to space vehicle observations. In this work we obtain an equally satisfactory fit by assuming a null quadrupole moment and least squares fitting of the displacement of the planetary dipole from the center of the planet. We find a best fit for a dipole displacement from the planet center of 0.033 R/sub m/ away from the solar direction, 0.025 R/sub m/ toward dawn in the magnetic equatorial plane, and 0.189 R/sub m/ northward along the magnetic dipole axis, where R/sub m/ is the planet radius. Therefore the presence of a magnetic quadrupole moment is not ruled out. The compressed dipole field more completely represents the field in the present work than in previous work where the intrinsic quadrupole field was not included in the magnetopause surface and field calculations. Moreover, we have corrected a programing error in previous work in the computation of dipole tilt lambda away from the sun. We find a slight increase for the planet dipole moment of 190γR/sub m/ 3 and a dipole tilt angle lambda away from the sun. We find a slight increase for the planet moment of 190γR/sub m/ 3 and a dipole tilt angle lambda of only 1.2 0 away from the sun. All other parameters are essentially unchanged

  14. Dipole Bands in 196Hg

    International Nuclear Information System (INIS)

    Lawrie, J. J.; Lawrie, E. A.; Newman, R. T.; Sharpey-Schafer, J. F.; Smit, F. D.; Msezane, B.; Benatar, M.; Mabala, G. K.; Mutshena, K. P.; Federke, M.; Mullins, S. M.; Ncapayi, N. J.; Vymers, P.

    2011-01-01

    High spin states in 196 Hg have been populated in the 198 Pt(α,6n) reaction at 65 MeV and the level scheme has been extended. A new dipole band has been observed and a previously observed dipole has been confirmed. Excitation energies, spins and parities of these bands were determined from DCO ratio and linear polarization measurements. Possible quasiparticle excitations responsible for these structures are discussed.

  15. A Note on the Dipole Coordinates

    OpenAIRE

    Kageyama, Akira; Sugiyama, Tooru; Watanabe, Kunihiko; Sato, Tetsuya

    2004-01-01

    A couple of orthogonal coordinates for dipole geometry are proposed for numerical simulations of plasma geophysics in the Earth's dipole magnetic field. These coordinates have proper metric profiles along field lines in contrast to the standard dipole coordinate system that is commonly used in analytical studies for dipole geometry.

  16. Large Mn25 single-molecule magnet with spin S = 51/2: magnetic and high-frequency electron paramagnetic resonance spectroscopic characterization of a giant spin state.

    Science.gov (United States)

    Murugesu, Muralee; Takahashi, Susumu; Wilson, Anthony; Abboud, Khalil A; Wernsdorfer, Wolfgang; Hill, Stephen; Christou, George

    2008-10-20

    The synthesis and structural, spectroscopic, and magnetic characterization of a Mn25 coordination cluster with a large ground-state spin of S = 51/2 are reported. Reaction of MnCl2 with pyridine-2,6-dimethanol (pdmH2) and NaN3 in MeCN/MeOH gives the mixed valence cluster [Mn25O18(OH)2(N3)12(pdm)6(pdmH)6]Cl2 (1; 6Mn(II), 18Mn(III), Mn(IV)), which has a barrel-like cage structure. Variable temperature direct current (dc) magnetic susceptibility data were collected in the 1.8-300 K temperature range in a 0.1 T field. Variable-temperature and -field magnetization (M) data were collected in the 1.8-4.0 K and 0.1-7 T ranges and fit by matrix diagonalization assuming only the ground state is occupied at these temperatures. The fit parameters were S = 51/2, D = -0.020(2) cm(-1), and g = 1.87(3), where D is the axial zero-field splitting parameter. Alternating current (ac) susceptibility measurements in the 1.8-8.0 K range and a 3.5 G ac field oscillating at frequencies in the 50-1500 Hz range revealed a frequency-dependent out-of-phase (chi(M)'') signal below 3 K, suggesting 1 to be a single-molecule magnet (SMM). This was confirmed by magnetization vs dc field sweeps, which exhibited hysteresis loops but with no clear steps characteristic of resonant quantum tunneling of magnetization (QTM). However, magnetization decay data below 1 K were collected and used to construct an Arrhenius plot, and the fit of the thermally activated region above approximately 0.5 K gave U(eff)/k = 12 K, where U(eff) is the effective relaxation barrier. The g value and the magnitude and sign of the D value were independently confirmed by detailed high-frequency electron paramagnetic resonance (HFEPR) spectroscopy on polycrystalline samples. The combined studies confirm both the high ground-state spin S = 51/2 of complex 1 and that it is a SMM that, in addition, exhibits QTM.

  17. Piezoelectric components wirelessly driven by dipole antenna-like electric field generator

    Energy Technology Data Exchange (ETDEWEB)

    Bhuyan, S., E-mail: elesatya@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Kumar, R.; Panda, S.K. [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Hu, J. [Lab of Precision Drive, Nanjing University of Aeronautics and Astronautics, Nanjing 210026 (China)

    2011-08-25

    Highlights: > Wireless energy transmission technique. > Dipole antenna-like electric field generator. > Piezoelecctric resonance. > Finite element analyses. > Simulations and experimental verifications. - Abstract: A new technique of transmitting electric energy wirelessly to piezoelectric components by using a dipole antenna-like electric field generator is explored. Two square size brass plate-shaped live and ground electrodes are used to form a dipole antenna-like electric field generator. When the dipole antenna-like electric field generator in electric resonance with an inductor, a maximum output power of 2.72 mW and an energy conversion efficiency of 0.0174% have been achieved wirelessly by the piezoelectric plate area of 40 mm{sup 2} operating in the thickness vibration mode, placed at the center 4 mm away from the antenna plane with an optimum electrical load of 1365 {Omega}, resonant frequency of 782 kHz, 1 cm electrodes separation, 2500 cm{sup 2} electrode area of dipole antenna-like structure, and input ac source power of 15.58 W applied to the series of dipole antenna-like structure and inductor. The theoretically calculated results have been validated by the experimental studies. It is seen that at the resonance frequency and optimum electrical load, the output power of the wirelessly driven piezoelectric component decreases with the size of piezoelectric component, distance of piezoelectric component from the electrode of antenna plane, but increases with the antenna electrode area.

  18. Passive wireless structural health monitoring sensor made with a flexible planar dipole antenna

    International Nuclear Information System (INIS)

    Jang, Sang-Dong; Kim, Jaehwan

    2012-01-01

    Cheap and efficient wireless sensors have been widely studied by electronics and communication technology development. In this paper, a flexible planar dipole antenna based passive wireless strain sensor has been investigated. The planar dipole antenna is designed for X band and made on a flexible polymer substrate using a conventional photolithography process. The fabricated dipole antenna is attached to a nonmetallic cantilever beam and monitors its bending strain. Mechanical strain and load impedance of the dipole antenna can change its resonance frequency, return loss and reflected signal. The return loss and reflected signals of the dipole antenna sensor are characterized by using a network analyzer. The strain sensitivity of the sensor is proportional to the return loss variation with the bending strain of the cantilever beam. The magnitude of reflected signals increases as the bending strain increases. (technical note)

  19. Electric and magnetic dipole moments of the neutron

    International Nuclear Information System (INIS)

    Ramsey, N.F.

    1977-01-01

    Experiments to measure the electric and magnetic dipole moments of the neutron are described. The apparatus used in this experiment is one to measure with high precision the precessional frequency of the neutron spin in a weak magnetic field with a neutron beam magnetic resonance apparatus similar to that used for measuring the magnetic moment of the neutron. Results of the measurement are presented. 52 references

  20. Minimum Q Electrically Small Spherical Magnetic Dipole Antenna - Theory

    DEFF Research Database (Denmark)

    Breinbjerg, Olav; Kim, Oleksiy S.

    2009-01-01

    The stored energies, radiated power, and quality factor of a magnetic-dipole antenna, consisting of a spherical electrical surface current density enclosing a magnetic core, is obtained through direct spatial integration of the internally and externally radiated field expressed in terms...... of spherical vector waves. The obtained quality factor agrees with that of Wheeler and Thal for vanishing free-space electric radius but holds also for larger radii and facilitates the optimal choice of permeability in the presence of the resonances....

  1. Multiple ionization of C{sub 60} in collisions with 2.33MeV/u O-ions and giant plasmon excitation

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, A.H. [Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 (India)]. E-mail: lokesh@tifr.res.in; Kadhane, U. [Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 (India); Misra, D. [Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 (India); Kumar, Ajay [Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 (India); Tribedi, L.C. [Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 (India)

    2007-03-15

    Single and multiple ionization of C{sub 60} in collisions with fast (v=9.7a.u.) O{sup q+} ions have been studied. Relative cross sections for production of C{sub 60}{sup 1+} to C{sub 60}{sup 4+} have been measured. The intensity ratios of double-to-single ionization agree very well with a model based on giant dipole plasmon resonance (GDPR). Almost linear increasing trend of the yields of single and double ionizations with projectile charge state is well reproduced by the single and double plasmon excitation mechanisms. The observed charge state independence of triple and quadruple ionization is in sharp contrast to the GDPR model.

  2. Stacks of SPS Dipole Magnets

    CERN Multimedia

    1974-01-01

    Stacks of SPS Dipole Magnets ready for installation in the tunnel. The SPS uses a separated function lattice with dipoles for bending and quadrupoles for focusing. The 6.2 m long normal conducting dipoles are of H-type with coils that are bent-up at the ends. There are two types, B1 (total of 360) and B2 (384). Both are for a maximum field of 1.8 Tesla and have the same outer dimensions (450x800 mm2 vxh) but with different gaps (B1: 39x129 mm2, B2: 52x92 mm2) tailored to the beam size. The yoke, made of 1.5 mm thick laminations, consists of an upper and a lower half joined together in the median plane once the coils have been inserted.

  3. Cryogenics in CEBAF HMS dipole

    International Nuclear Information System (INIS)

    Bogensberger, P.; Ramsauer, F.; Brindza, P.; Wines, R.; Koefler, H.

    1994-01-01

    The paper will report upon the final design, manufacturing and tests of CEBAF's HMS Dipole cryogenic equipment. The liquid nitrogen circuits, the helium circuits and thermal insulation of the magnet will be addressed. The cryogenic reservoir and control module as an integral part of the HMS Dipole magnet will be presented. The construction, manufacturing, tests and final performance of the HMS Dipole cryogenic system will be reported. The LN 2 circuit and the He circuit are tied together by the control system for cool down, normal operation and standby. This system monitors proper temperature differences between both circuits and controls the cryogenic supply to meet the constraints. Implementation of the control features for the cryogenic system into the control system will be reported

  4. Derivation of the dipole map

    International Nuclear Information System (INIS)

    Ali, Halima; Punjabi, Alkesh; Boozer, Allen

    2004-01-01

    In our method of maps [Punjabi et al., Phy. Rev. Lett. 69, 3322 (1992), and Punjabi et al., J. Plasma Phys. 52, 91 (1994)], symplectic maps are used to calculate the trajectories of magnetic field lines in divertor tokamaks. Effects of the magnetic perturbations are calculated using the low MN map [Ali et al., Phys. Plasmas 11, 1908 (2004)] and the dipole map [Punjabi et al., Phys. Plasmas 10, 3992 (2003)]. The dipole map is used to calculate the effects of externally located current carrying coils on the trajectories of the field lines, the stochastic layer, the magnetic footprint, and the heat load distribution on the collector plates in divertor tokamaks [Punjabi et al., Phys. Plasmas 10, 3992 (2003)]. Symplectic maps are general, efficient, and preserve and respect the Hamiltonian nature of the dynamics. In this brief communication, a rigorous mathematical derivation of the dipole map is given

  5. Electrified BPS giants: BPS configurations on giant gravitons with static electric field

    International Nuclear Information System (INIS)

    Ali-Akbari, Mohammad; Sheikh-Jabbari, Mohammad Mahdi

    2007-01-01

    We consider D3-brane action in the maximally supersymmetric type IIB plane-wave background. Upon fixing the light-cone gauge, we obtain the light-cone Hamiltonian which is manifestly supersymmetric. The 1/2 BPS solutions of this theory (solutions which preserve 16 supercharges) are either of the form of spherical three branes, the giant gravitons, or zero size point like branes. We then construct specific classes of 1/4 BPS solutions of this theory in which static electric field on the brane is turned on. These solutions are deformations about either of the two 1/2 BPS solutions. In particular, we study in some detail 1/4 BPS configurations with electric dipole on the three sphere giant, i.e. BIons on the giant gravitons, which we hence call BIGGons. We also study BPS configurations corresponding to turning on a background uniform constant electric field. As a result of this background electric field the three sphere giant is deformed to squashed sphere, while the zero size point like branes turn into circular or straight fundamental strings in the plane-wave background, with their tension equal to the background electric field

  6. Nanodielectrics with giant permittivity

    Indian Academy of Sciences (India)

    Following the prediction, during the last couple of years we have investigated the effect of giant permittivity in one-dimensional systems of conventional metals and conjugated polymer chains. In this article, we have tried to summarize the works on giant permittivity and finally the fabrication of nanocapacitor using metal ...

  7. Raising the last LEP dipole

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    The last of the 3280 dipole magnets from the Large Electron-Positron (LEP) collider is seen on its journey to the surface on 12 February 2002. The LEP era, which began at CERN in 1989 and ended 2000, comes to an end.

  8. Locating a buried magnetic dipole

    Energy Technology Data Exchange (ETDEWEB)

    Caffey, T.W.H.

    1977-01-01

    The theoretical basis and required computations for locating a buried magnetic dipole are outlined. The results are compared with measurements made with a tiltable coil lowered to a depth of 20 m in a vertical borehole within a three-layered earth. this work has application to the rescue of trapped miners. 3 figures, 1 table. (RWR)

  9. Particle electric dipole-moments

    Energy Technology Data Exchange (ETDEWEB)

    Pendlebury, J M [Sussex Univ., Brighton (United Kingdom)

    1997-04-01

    The incentive to detect particle electric dipole-moments, as a window on time-reversal violation, remains undiminished. Efforts to improve the measurements for the neutron, the electron and some nuclei are still making rapid progress as more powerful experimental methods are brought to bear. A new measurement for the neutron at ILL is presented. (author). 7 refs.

  10. 5cm aperture dipole studies

    International Nuclear Information System (INIS)

    McInturff, A.D.; Bossert, R.; Carson, J.; Fisk, H.E.; Hanft, R.; Kuchnir, M.; Lundy, R.; Mantech, P.; Strait, J.

    1986-01-01

    The results obtained during the evolution of the design, construction, and testing program of the design ''B'' dipole are presented here. Design ''B'' is one of the original three competing designs for the Superconducting Super Collider ''SSC'' arc dipoles. The final design parameters were as follows: air cored (less than a few percent of the magnetic field derived from any iron present), aluminum collared, two layered winding, 5.5T maximum operating field, and a 5 cm cold aperture. There have been fourteen 64 cm long 5 cm aperture model dipoles cold tested (at 4.3K and less) in this program so far. There was a half length full size (6m) mechanical analog (M-10) built and tested to check the cryostat's mechanical design under ramping and quench conditions. Several deviations from the ''Tevatron'' dipole fabrication technique were incorporated, for example the use of aluminum collars instead of stainless steel. The winding technique variations explored were ''dry welding,'' a technique with the cable covered with Kapton insulation only and ''wet winding'' where the Kapton was covered with a light coat of ''B'' stage epoxy. Test data include quench currents, field quality (Fourier multipole co-efficients), coil magnetization, conductor current performance, and coil loading. Quench current, loss per cycle, and harmonics were measured as a function of the magnitude and rate of change of the magnetic field, and helium bath temperature

  11. The Collider dipole magnet program

    International Nuclear Information System (INIS)

    Baldi, R.W.; Bailey, R.; Bever, D.; Bogart, L.; Gigg, G.; Packer, M.; Page, L.; Stranberg, N.

    1991-01-01

    The Superconducting Super Collider will consist of more large superconducting magnets than have been built to date. Over 12,000 superconducting magnets are required and more than 8,000 will be Collider dipoles. The dipole magnet program is on the critical path of the project and requires the optimized utilization of the Nation's resources - National Laboratories, Universities and Industry. General Dynamics and Westinghouse Electric Corporation have been chosen as the Leader and Follower companies for the design of producible magnets and the manufacturing of the SSC dipoles. Industry has the necessary experience, skills and facilities required to produce reliable and cost effective dipole magnets. At peak production, 10 CDMs per day, very large quantities (nearly 130 metric tonnes/day) of materials will have to be procured from companies nationwide and fabricated into defect-free magnets. A key element of the SSCL's strategy to produce the most efficient CDM program is to employ the Leader-Follower approach, with the Leader transferring technology from the laboratories to the Leader's facility, fully integrating the Follower in the producibility and tooling/factory design efforts, and assisting the Follower in magnet qualification tests. General Dynamics is ready to help build America's most powerful research tool. Management is in place, the facilities are ready for activation and resources are available for immediate assignment

  12. A Tale of Two Dipoles

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach

    2006-01-01

    A number of antenna topics may be treated by studying just two parallel, closely spaced electrical dipoles. They form an array and they may be coupled to form a single antenna with one port, or coupled through a coupling network to form a multiport antenna. The situations discussed are the creation...

  13. Multiscale dipole relaxation in dielectric materials

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt

    2016-01-01

    Dipole relaxation from thermally induced perturbations is investigated on different length scales for dielectric materials. From the continuum dynamical equations for the polarisation, expressions for the transverse and longitudinal dipole autocorrelation functions are derived in the limit where ...

  14. Dipole rescattering and the nuclear structure function

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, F. [Depto de Ciencias Exatas e da Terra, Universidade Federal de Sao Paulo, SP (Brazil); Goncalves, V. P. [Instituto de Fisica e Matematica, Universidade Federal de Pelotas, Caixa Postal 354, CEP 96010-900, Pelotas, RS (Brazil); Navarra, F. S.; Oliveira, E. G. [Instituto de Fisica, Universidade de Sao Paulo Rua do Matao, Travessa R, 187, 05508-090 Sao Paulo, SP (Brazil)

    2013-03-25

    In the framework of the dipole model, we study the effects of the dipole multiple scatterings in a nuclear target and compute the nuclear structure function. We compare different unitarization schemes and confront our results with the E665 data.

  15. New bound on neutrino dipole moments from globular-cluster stars

    Science.gov (United States)

    Raffelt, Georg G.

    1990-01-01

    Neutrino dipole moments mu(nu) would increase the core mass of red giants at the helium flash by delta(Mc) = 0.015 solar mass x mu(nu)/10 to the -12th muB (where muB is the Bohr magneton) because of enhanced neutrino losses. Existing measurements of the bolometric magnitudes of the brightest red giants in 26 globular clusters, number counts of horizontal-branch stars and red giants in 15 globular clusters, and statistical parallax determinations of field RR Lyr luminosities yield delta(Mc) = 0.009 + or - 0.012 solar mass, so that conservatively mu(nu) is less than 3 x 10 to the -12th muB.

  16. Resonances and anti-resonances in the material parameters of 2-D dielectric ENG, MNG, and DNG materials

    DEFF Research Database (Denmark)

    Wu, Yunqiu; Arslanagic, Samel

    The resonant/anti-resonant behavior of parameters extracted by the S-parameter method for two-dimensional epsilon-, mu- and double-negative (ENG, MNG, DNG) materials is investigated. The unit cells consist of infinite dielectric cylinders supporting electric dipole, magnetic dipole, or both....... It is shown that the extraction procedure yields one resonant material parameter, and one anti-resonant material parameter in MNG and ENG configurations. However, both parameters display an over-all resonant response in DNG configurations where electric and magnetic dipole modes are excited simultaneously....

  17. Enhanced terahertz magnetic dipole response by subwavelength fiber

    Directory of Open Access Journals (Sweden)

    Shaghik Atakaramians

    2018-05-01

    Full Text Available Dielectric sub-wavelength particles have opened up a new platform for realization of magnetic light. Recently, we have demonstrated that a dipole emitter by a sub-wavelength fiber leads to an enhanced magnetic response. Here, we experimentally demonstrate an enhanced magnetic dipole source in the terahertz frequency range. By placing the fiber next to the hole in a metal screen, we find that the radiation power can be enhanced more than one order of magnitude. The enhancement is due to the excitation of the Mie-type resonances in the fiber. We demonstrate that such a system is equivalent to a double-fiber system excited by a magnetic source. This coupled magnetic dipole and optical fiber system can be considered a unit cell of metasurfaces for manipulation of terahertz radiation and is a proof-of-concept of a possibility to achieve enhanced radiation of a dipole source in proximity of a sub-wavelength fiber. It can also be scaled down to optical frequencies opening up promising avenues for developing integrated nanophotonic devices such as nanoantennas or lasers on fibers.

  18. Dynamics of a nonlinear dipole vortex

    DEFF Research Database (Denmark)

    Hesthaven, J.S.; Lynov, Jens-Peter; Nielsen, A.H.

    1995-01-01

    A localized stationary dipole solution to the Euler equations with a relationship between the vorticity and streamfunction given as omega=-psi+psi(3) is presented. By numerical integration of the Euler equations this dipole is shown to be unstable. However, the initially unstable dipole reorganiz...

  19. Formation of dislocation dipoles in irradiated graphite

    International Nuclear Information System (INIS)

    Niwase, Keisuke

    2005-01-01

    Recently, we have proposed a dislocation dipole accumulation model to explain the irradiation-induced amorphization of graphite. However, the structure of dislocation dipole in the hexagonal networks is still an open question at the atomic-level. In this paper, we propose a possible formation process of the dislocation dipole

  20. Polarization electric dipole moment in nonaxial nuclei

    International Nuclear Information System (INIS)

    Denisov, V.Yu.; Davidovskaya, O.I.

    1996-01-01

    An expression for the macroscopic polarization electric dipole moment is obtained for nonaxial nuclei whose radii of the proton and neutron surfaces are related by a linear equation. Dipole transitions associated with the polarization electric dipole moment are analyzed for static and dynamical multipole deformations