C12(α,γ)O16 capture cross section below 3.2 MeV


Journal Article

The C12(α,γ)O16 capture cross section was measured for α-particle energies between 1.86 MeV (σ=1.1±0.4 nb) and 3.11 MeV (σ=29±4 nb) using a pulsed He+4 beam from the ORNL 6-MV Van de Graaff accelerator and a 23- by 30-cm NaI(Tl) crystal viewed by six matched, bialkali photomultiplier tubes. An upper limit was obtained for the capture cross section at Eα=1.6 MeV. The over-all time resolution (full width at half maximum) of the system for 8-10-MeV pulses due to γ rays is 2.7 nsec. Enriched (99.94%) C12 targets ranging in thickness from 98 to 178 μg/cm2 were used. Pulses resulting from fast neutrons [from the C13(α,n)O16 reaction] interacting with the NaI(Tl) crystal were further separated from true γ pulses through the use of a new technique based on rise-time distribution differences of the respective neutron- and γ-ray-produced pulses. The face of the crystal (shielded with a 10.2 cm thickness of LiH6) was 12.2 cm from the target. The astrophysical significance of this reaction in the helium-burning sequence of stellar nucleosynthesis is also discussed. © 1970 The American Physical Society.

Full Text

Duke Authors

Cited Authors

  • Jaszczak, RJ; Gibbons, JH; MacKlin, RL

Published Date

  • January 1, 1970

Published In

Volume / Issue

  • 2 / 1

Start / End Page

  • 63 - 69

International Standard Serial Number (ISSN)

  • 0556-2813

Digital Object Identifier (DOI)

  • 10.1103/PhysRevC.2.63

Citation Source

  • Scopus