Radiative Strength Functions in 172Yb below 8 Me V
We have measured prompt {gamma} rays after thermal and resonant neutron capture in {sup 171}Yb. The {gamma} rays were measured with three high resolution ({approx}3 keV) and high efficiency (two {approx}80% Ge(HP) and one {approx}200% segmented Clover) detectors. We have obtained singles and two-fold coincidence spectra as function of neutron energy using the time-of-flight technique. Two-fold coincidences where the summed energy adds up to the neutron binding energy B{sub n} or to B{sub n} minus the energy of the first excited stated ({approx}79 keV) will be used to determine the multipolarity of the pygmy resonance in {sup 172}Yb. This pygmy resonance is a resonant structure in the radiative strength function around {approx}3 MeV in deformed rare earth nuclei [1]. The following goals were met: (1) We have shown the feasibility of prompt, high-resolution {gamma} spectroscopy at FP14 after thermal as well as resonant neutron capture. (2) Online analysis shows that sufficient statistics ({approx}7000 counts) are expected in each of the two relevant peaks in the summed-energy spectrum. Analysis of the experiment is in progress. It still remains to show that the multipolarity of the pygmy resonance can be determined experimentally from two-step cascade intensities.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15002354
- Report Number(s):
- UCRL-ID-147425; TRN: US0400727
- Resource Relation:
- Other Information: PBD: 6 Feb 2002
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BINDING ENERGY
CAPTURE
CLOVER
EFFICIENCY
MULTIPOLARITY
NEUTRON REACTIONS
NEUTRONS
RARE EARTH NUCLEI
RESOLUTION
RESONANCE
SPECTRA
SPECTROSCOPY
STATISTICS
STRENGTH FUNCTIONS