Spectroscopy of /sup 18/O: Radiative capture, /sup 14/C(. cap alpha. ,. gamma. )/sup 18/O

Journal Article · Thu Oct 01 04:00:00 EDT 1987 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.36.1256· OSTI ID:6011993

Gai, M; Keddy, R; Bromley, D A; Olness, J W; Warburton, E K

The electromagnetic deexcitation of the six known /sup 14/C+..cap alpha.. resonances in the range E/sub ..cap alpha../ = 1.7--2.7 MeV was observed with a Ge(Li) detector. Results for the branching ratios of the 7.62-, 8.04-, and 8.13-MeV /sup 18/O levels were found to be in agreement with previous measurements. Deexcitation of the 7.86-, 8.21-, and 8.28-MeV levels was observed for the first time. The radiative widths of these three (..cap alpha..,..gamma..) resonances were determined. Electromagnetic transition strengths were derived for all the resonances from the gamma-ray branching ratios and the total radiative widths. A selective and enhanced E1 decay (--10/sup -2/ W.u.) of the 3/sub 3//sup -/ state is observed; among the available 2/sup +/ states lower in excitation, this 3/sub 3//sup -/ state is observed to deexcite only to the 2/sub 3//sup +/ state. The 2/sub 3//sup +/ state is well understood to involve excitations of the /sup 16/O core, whereas the 2/sub 2//sup +/ and 2/sub 1//sup +/ states arise mainly from simple two neutron (sd-shell) configurations. The relevance of the ..cap alpha..+ /sup 14/C radiative capture reactions for nucleosynthesis of heavier elements, at the hadronization phase of the big bang, is discussed.

• Research Organization: A. W. Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06511
• OSTI ID: 6011993
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 36:4; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651320* -- Nuclear Properties & Reactions
A=6-19
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACCELERATORS
ALPHA REACTIONS
ANGULAR MOMENTUM
BRANCHING RATIO
CAPTURE
CARBON 14 TARGET
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
E1-TRANSITIONS
ELECTROMAGNETIC RADIATION
ELECTROSTATIC ACCELERATORS
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EXCITATION FUNCTIONS
FUNCTIONS
GAMMA RADIATION
IONIZING RADIATIONS
ISOTOPES
LIGHT NUCLEI
MEV RANGE
MEV RANGE 01-10
MULTIPOLE TRANSITIONS
NUCLEAR REACTIONS
NUCLEI
NUCLEOSYNTHESIS
OXYGEN 18
OXYGEN ISOTOPES
PARITY
PARTICLE PROPERTIES
RADIATIONS
RESONANCE
SPIN
STABLE ISOTOPES
SYNTHESIS
TARGETS
VAN DE GRAAFF ACCELERATORS