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

Journal Article · Mon Feb 26 00:00:00 EST 2007 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2713535· OSTI ID:21056759

Tonchev, A P; Howell, C R; Tornow, W ^[1]; Angell, C; Boswell, M; Karwowski, H J ^[2]; Chyzh, A; Kelley, J H ^[3]; Tsoneva, N ^[4]; Wu, Y K ^[5]

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1. Duke University, Department of Physics, Box 90308, Durham, NC 27708-0308 (United States)
2. University of North Carolina, Department of Physics and Astronomy, Chapel Hill, NC 27599-3255 (United States)
3. North Carolina State University, Department of Physics, Box 8202, Raleigh, NC 27695-8202 (United States)
4. Institute of Theoretical Physics, University of Giessen, Heinrich-Buff-Ring 16, D-35392, Giessen (Germany)
5. Duke University, Durham, NC 27708-0319 (United States)

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.

• OSTI ID: 21056759
• Journal Information: AIP Conference Proceedings, Vol. 891, 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); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

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