Common thresholds and the role of deformations in the photoexcitation of isomers

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.46.952· OSTI ID:7157116

Collins, C B; Carroll, J J; Taylor, K N; Richmond, D G; Sinor, T W ^[1]; Huber, M; von Neumann-Cosel, P; Richter, A; Ziegler, W ^[2]

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1. Center for Quantum Electronics, University of Texas at Dallas, P.O. Box 830688, Richardson, Texas 75083 (United States)
2. Institut fuer Kernphysik, Technische Hochschule Darmstadt, D-6100 Darmstadt (Germany)

Photoexcitations of the short-lived isomers {sup 167}Er{sup {ital m}}, {ital T}{sub 1/2}=2.28 s, {sup 179}Hf{sup {ital m}}, {ital T}{sub 1/2}=18.68 s, {sup 191}Ir{sup {ital m}}, {ital T}{sub 1/2}=4.94 s, and {sup 197}Au{sup {ital m}}, {ital T}{sub 1/2}=7.8 s, were produced with bremsstrahlung from the superconducting Darmstadt linear accelerator. Excitation functions were measured for the population of these isomers by ({gamma},{gamma}{prime}) reactions between 2 and 7 MeV. They indicated that the isomers were excited by resonant absorption through isolated intermediate states having integrated cross sections in excess of 10{sup {minus}26} cm{sup 2} keV, i.e., values about 1000 times larger than most ({gamma},{gamma}{prime}) activation reactions reported previously although they were comparable to those reported earlier for the depopulating reaction {sup 180}Ta{sup {ital m}}({gamma},{gamma}{prime}){sup 180}Ta. In all four nuclei a common onset was observed near 2.5 MeV for intermediate states with strengths much larger than those occurring at lower energies. The summed cross sections exhibit a clear correlation with the ground state deformations.

• OSTI ID: 7157116
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 46:3; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

663410* -- Photonuclear Reactions & Photon Scattering-- (1992-)
663570 -- Nuclear Mass Ranges-- A=150-189-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
DATA
DEFORMATION
ENERGY LEVELS
ENERGY RANGE
ERBIUM 167 TARGET
EXCITED STATES
EXPERIMENTAL DATA
GAMMA SPECTRA
GOLD 197 TARGET
HAFNIUM 179 TARGET
INELASTIC SCATTERING
INFORMATION
IRIDIUM 191 TARGET
ISOMERS
MEV RANGE
MEV RANGE 01-10
NUCLEAR DEFORMATION
NUCLEAR REACTIONS
NUMERICAL DATA
PHOTONUCLEAR REACTIONS
SCATTERING
SPECTRA
TARGETS