Photon Decay of Giant Resonances
Photon Decay of Giant Resonances

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Published: 1984

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Measurements have been made of the photon decay of the giant multipole resonances in 2°8Pb. The giant resonances were excited by inelastic scattering of 380 MeV 17O projectile and the photons were detected in the ORNL Spin Spectrometer. The results show a quadrupole resonance ground state gamma branch of 20% while only less than or equal to 2% of the GQR decay proceeds through the 2.6 MeV, 3− state. Nearly one half of the GQR decay through a 3− state at 4.974 MeV. Photon decay from the dipole and monopole resonances and high spin resonances (4+,6+) are also observed.

Photon Decay of Giant Multipole Resonances
Photon Decay of Giant Multipole Resonances

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Published: 1990

Total Pages: 15

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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 provided 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 shingles spectra. 26 refs., 16 figs., 1 tab.

Excitation and Photon Decay of Giant Multipole Resonances - the Role and Future of Medium-energy Heavy Ions
Excitation and Photon Decay of Giant Multipole Resonances - the Role and Future of Medium-energy Heavy Ions

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Published: 1988

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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 photon decay of giant resonances following excitation by 22 and 84 MeV/nucleon 17O 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 2°8Pb isovector quadrupole resonance using its gamma decay are presented.

Excitation and Photon Decay of Giant Multipole Resonances
Excitation and Photon Decay of Giant Multipole Resonances

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Published: 1990

Total Pages: 14

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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.

Heavy Ion Excitation and Photon Decay of Giant Resonances
Heavy Ion Excitation and Photon Decay of Giant Resonances

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Published: 1983

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Results are presented for excitation of giant multipole resonances by inelastic scattering of 350 and 500 MeV 16O projectiles from 9°Zr and 2°8Pb. The giant quadrupole resonance is excited with large cross sections and a very large resonance peak to continuum ratio is obtained. Extracted cross sections agree with DWBA calculations which use standard collective model form factors. Using 380 MeV 170 to excite the giant resonances, the .gamma.-ray decay has been measured for the giant quadrupole resonance region of 2°8Pb. 10 references.

Giant Resonance Decay
Giant Resonance Decay

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Published: 1990

Total Pages: 17

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Decay studies of giant multipole resonances are discussed, emphasizing the role of Coulomb excitation with intermediate energy heavy ions, which can provide very large cross sections for both isoscalar and isovector resonances. We discuss measurement of the photon decay of one and two phonon giant resonances, reporting results where available. 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. 30 refs., 16 figs., 1 tab.

Giant Resonances
Giant Resonances

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Published: 1989

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A review of some recent developments in the field of giant multipole resonances is presented. Particular emphasis is placed on directions that the authors feel will be followed in this field during the next several years. In particular, the use of high-energy heavy ions to excite the giant resonances is shown to provide exciting new capabilities for giant resonance studies. Among subjects covered are: Coulomb excitation of giant resonances, photon decay of giant resonances, the recent controversy over the identity of the giant monopole resonance, the most recent value for incompressibility of nuclear matter from analysis of giant monopole data, the isospin character of the 63 A/sup /minus/1/3/ GQR, agreement between (e, e/prime/) and (hadron, hadron/prime/) excitation of the giant quadrupole resonance, prospects for multiphonon giant resonance observation, and isolation of the isovector giant quadrupole resonance. 55 refs., 23 figs., 4 tabs.

Giant Resonances and Intermediate Energy Heavy Ions
Giant Resonances and Intermediate Energy Heavy Ions

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Published: 1991

Total Pages: 11

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We briefly explore how large cross sections for excitation of both isoscalar and isovector giant multipole resonances which can be obtained using intermediate energy heavy-ion reactions can be utilized in photon-decay coincidence experiments to provide new information on subjects ranging from basic nuclear structure properties to resonance damping and pre-compound decay. We also discuss experiments in which photon-decay techniques are used as a tag to isolate and identify very weakly excited modes, enabling us to explore such diverse subjects as hadronic excitation of the giant dipole resonance, the distribution of isovector quadrupole strength in 2°8Pb, and the excitation of two-phonon giant resonance strength. 25 refs., 12 figs.

Excitation and Decay of Giant Multipole Resonances in Intermediate Energy Heavy Ion Reactions
Excitation and Decay of Giant Multipole Resonances in Intermediate Energy Heavy Ion Reactions

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Published: 1989

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The role of intermediate energy heavy ions in the study of giant multipole resonances is explored, with emphasis on gamma decay coincidence experiments. Experiments on 2°8Pb bombarded by 84 MeV/nucleon 17O are discussed and compared with earlier work at 22 MeV/nucleon. The role of Coulomb excitation in the 84 MeV/nucleon data is emphasized and some consequences for study of isovector resonance strength are explored. A comparison of the excitation and decay of the isovector giant dipole resonance in 2°8Pb and 2°9Bi excited with 84 MeV/nucleon 17O scattering is presented. 35 refs., 16 figs., 1 tab.