The {beta}-delayed {alpha} spectrum of {sup 16}N and the {sup 12}C({alpha},{gamma}){sup 16}O cross section at low energies

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Bulletin of the American Physical Society

OSTI ID:243779

Buchmann, L

The low-energy part of the {beta}{alpha}-decay spectrum of {sup 16}N permits the determination of the {alpha}+{sup 12}C reduced width of the E{sub x}=7.12 MeV, sub-threshold state of {sup 16}O. This state, in turn, dominates the low energy p-wave capture amplitude of the astrophysically important reaction {sup 12}C({alpha},{gamma}){sup 16}O. The {alpha}-spectrum following the decay of {sup 16}N has been measured by producing a low-energy {sup 16}N beam with the TRIUMF isotope separator TISOL, stopping the {sup 16}N nuclei in a foil, rotating it, and counting the {alpha}-particles and {sup 12}C recoil nuclei, in coincidence, in thin surface-barrier detectors. In addition to obtaining the {alpha}-spectrum, the authors determine the detector response by this method. These data, which includes 10{sup 6} {alpha}-{sup 12}C coincidences, show that the main {alpha}-peak is accompanied by a lower-energy interference structure, as predicted by several authors. The spectrum obtained has been fitted by a K-matrix parameterization which includes the measured {sup 12}C({alpha},{gamma}){sup 16}O cross sections. A value of S{sub E1}(0.3)=57{+-}13 keV{center_dot}b has been derived for the E1 part of the {sup 12}C({alpha},{gamma}){sup 16}O S factor at E{sub c.m.}0.3 MeV.

• OSTI ID: 243779
• Report Number(s): CONF-9304297--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 2 Vol. 38; ISSN BAPSA6; ISSN 0003-0503
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALPHA DECAY
ALPHA REACTIONS
BETA DECAY
CARBON 12
NITROGEN 15
NUCLEOSYNTHESIS
OXYGEN 16
S PROCESS