Intermediate structure in the photoexcitation of [sup 77]Se[sup [ital m]], [sup 79]Br[sup [ital m]], and [sup 137]Ba[sup [ital m]]

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.48.2238· OSTI ID:5915979

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

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1. Center for Quantum Electronics, The University of Texas at Dallas, P.O. Box 830688, Richardson, Texas 75083 (United States) Institute for Theoretical Physics, Proeftuinstraat 86, B-9000 Gent (Belgium) Institut fuer Kernphysik, Technische Hochschule Darmstadt, Schlossgartenstrasse 9, D-64289 Darmstadt (Germany) Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Head Post Office, P.O. Box 79, Moscow (Russian Federation)

Continuing the systematic investigation into the photoexcitation of isomers over wide mass and energy ranges, the production of [sup 77]Se[sup [ital m]], [sup 79]Br[sup [ital m]], and [sup 137]Ba[sup [ital m]] was studied with the bremsstrahlung facility at the superconducting Darmstadt linear accelerator. These isomers have half-lives on the order of seconds. Excitation functions were measured for the ([gamma],[gamma][prime]) reactions populating the metastable states for energies of 2--7 MeV and the important intermediate states were identified. Nuclear structure calculations with the quasiparticle-phonon model for [sup 79]Br and the particle- (hole-) core coupling approach for [sup 137]Ba gave satisfactory descriptions for the strength and position of the dominant mediating levels. Admixtures of fragmented outershell single-particle strength shifted to low energies were identified as essential features of the wave functions of those states. Intermediate states in [sup 77]Se displayed very large strengths compared to other isomers in the same mass region, providing further support for the correlation between integrated cross sections and ground state deformations recently discovered in the [ital A]=160--200 mass region. Such an enhancement would considerably improve the feasibility of a gamma-ray laser based on the sudden deexcitation of isomeric populations in deformed nuclei.

• OSTI ID: 5915979
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 48:5; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

663410* -- Photonuclear Reactions & Photon Scattering-- (1992-)
663550 -- Nuclear Mass Ranges-- A=59-89-- (1992-)
663560 -- Nuclear Mass Ranges-- A=90-149-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARIUM 137 TARGET
BROMINE 79 TARGET
CROSS SECTIONS
DEFORMED NUCLEI
ELECTROMAGNETIC RADIATION
ENERGY LEVELS
ENERGY RANGE
EXCITATION FUNCTIONS
EXCITED STATES
FUNCTIONS
GAMMA RADIATION
IONIZING RADIATIONS
ISOMERIC NUCLEI
MEV RANGE
MEV RANGE 01-10
NUCLEAR REACTIONS
NUCLEI
PHOTONUCLEAR REACTIONS
RADIATIONS
SELENIUM 77 TARGET
TARGETS