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Title: Study of Collective Dipole Excitations below the Giant Dipole Resonance at HI{gamma}S

Abstract

The High-Intensity Gamma-ray Source utilizing intra-cavity back-scattering of free electron laser photons from relativistic electrons allows one to produce a unique beam of high-flux gamma rays with 100% polarization and selectable energy and energy resolution which is ideal for low-energy {gamma}-ray scattering experiments. Nuclear resonance fluorescence experiments have been performed on N=82 nuclei. High sensitivity studies of E1 and M1 excitations at energies close to the neutron emission threshold have been performed. The method allows the determination of excitation energies, spin, parities, and decay branching ratios of the pygmy dipole mode of excitation. The observations are compared with calculations using statistical and quasi-particle random-phase approximations.

Authors:
; ;  [1];  [2]; ; ;  [3];  [2]; ;  [4];  [2];  [5];  [6];  [2]
  1. Duke University, Department of Physics, Box 90308, Durham, NC 27708-0308 (United States)
  2. (United States)
  3. University of North Carolina, Department of Physics and Astronomy, Chapel Hill, NC 27599-3255 (United States)
  4. North Carolina State University, Department of Physics, Box 8202, Raleigh, NC 27695-8202 (United States)
  5. Institute of Theoretical Physics, University of Giessen, Heinrich-Buff-Ring 16, D-35392, Giessen (Germany)
  6. Duke University, Durham, NC 27708-0319 (United States)
Publication Date:
OSTI Identifier:
21056759
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 891; Journal Issue: 1; Conference: 6. Symposium on nuclear physics, Tours (France), 5-8 Sep 2006; Other Information: DOI: 10.1063/1.2713535; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BACKSCATTERING; BRANCHING RATIO; ELECTRONS; ENERGY RESOLUTION; EXCITATION; GAMMA RADIATION; GAMMA SOURCES; GIANT RESONANCE; NEUTRON EMISSION; PARITY; PHOTON-NUCLEON INTERACTIONS; PHOTONUCLEAR REACTIONS; POLARIZATION; QUASI PARTICLES; RANDOM PHASE APPROXIMATION; RESONANCE FLUORESCENCE; SENSITIVITY ANALYSIS; SPIN; STATISTICAL MODELS

Citation Formats

Tonchev, A. P., Howell, C. R., Tornow, W., TUNL, Department of Physics, Box 90308, Durham, NC 27708-0308, Angell, C., Boswell, M., Karwowski, H. J., TUNL, Department of Physics and Astronomy, Chapel Hill, NC 27599-3255, Chyzh, A., Kelley, J. H., TUNL, Department of Physics, Box 8202, Raleigh, NC 27695-8202, Tsoneva, N., Wu, Y. K., and Duke Free Electron Laser Laboratory, Durham, NC 27708-0319. Study of Collective Dipole Excitations below the Giant Dipole Resonance at HI{gamma}S. United States: N. p., 2007. Web. doi:10.1063/1.2713535.
Tonchev, A. P., Howell, C. R., Tornow, W., TUNL, Department of Physics, Box 90308, Durham, NC 27708-0308, Angell, C., Boswell, M., Karwowski, H. J., TUNL, Department of Physics and Astronomy, Chapel Hill, NC 27599-3255, Chyzh, A., Kelley, J. H., TUNL, Department of Physics, Box 8202, Raleigh, NC 27695-8202, Tsoneva, N., Wu, Y. K., & Duke Free Electron Laser Laboratory, Durham, NC 27708-0319. Study of Collective Dipole Excitations below the Giant Dipole Resonance at HI{gamma}S. United States. doi:10.1063/1.2713535.
Tonchev, A. P., Howell, C. R., Tornow, W., TUNL, Department of Physics, Box 90308, Durham, NC 27708-0308, Angell, C., Boswell, M., Karwowski, H. J., TUNL, Department of Physics and Astronomy, Chapel Hill, NC 27599-3255, Chyzh, A., Kelley, J. H., TUNL, Department of Physics, Box 8202, Raleigh, NC 27695-8202, Tsoneva, N., Wu, Y. K., and Duke Free Electron Laser Laboratory, Durham, NC 27708-0319. Mon . "Study of Collective Dipole Excitations below the Giant Dipole Resonance at HI{gamma}S". United States. doi:10.1063/1.2713535.
@article{osti_21056759,
title = {Study of Collective Dipole Excitations below the Giant Dipole Resonance at HI{gamma}S},
author = {Tonchev, A. P. and Howell, C. R. and Tornow, W. and TUNL, Department of Physics, Box 90308, Durham, NC 27708-0308 and Angell, C. and Boswell, M. and Karwowski, H. J. and TUNL, Department of Physics and Astronomy, Chapel Hill, NC 27599-3255 and Chyzh, A. and Kelley, J. H. and TUNL, Department of Physics, Box 8202, Raleigh, NC 27695-8202 and Tsoneva, N. and Wu, Y. K. and Duke Free Electron Laser Laboratory, Durham, NC 27708-0319},
abstractNote = {The High-Intensity Gamma-ray Source utilizing intra-cavity back-scattering of free electron laser photons from relativistic electrons allows one to produce a unique beam of high-flux gamma rays with 100% polarization and selectable energy and energy resolution which is ideal for low-energy {gamma}-ray scattering experiments. Nuclear resonance fluorescence experiments have been performed on N=82 nuclei. High sensitivity studies of E1 and M1 excitations at energies close to the neutron emission threshold have been performed. The method allows the determination of excitation energies, spin, parities, and decay branching ratios of the pygmy dipole mode of excitation. The observations are compared with calculations using statistical and quasi-particle random-phase approximations.},
doi = {10.1063/1.2713535},
journal = {AIP Conference Proceedings},
number = 1,
volume = 891,
place = {United States},
year = {Mon Feb 26 00:00:00 EST 2007},
month = {Mon Feb 26 00:00:00 EST 2007}
}