Astrophysical reaction rate for the 8Li(n,γ)9Li reaction
Abstract
An attempt was made to measure the excitation function of the cross section for the 8Li(n,γ)9Li reaction by performing the inverse reaction 9Li(γ,n)8Li, with the equivalent photons in the electric field of nuclei in a Pb target providing the γ rays for the reaction. The energy spectrum of lithium nuclei in coincidence with neutrons had no discernible peak where any beam-velocity 8Li’s would be located. Statistically, a Gaussian-shaped 8Li peak could have been present with 30±29 counts, which we interpreted as consistent with zero, with a two-standard-deviation upper limit of 87 counts. Using the fact that neutron capture on 8Li must be dominantly s-wave capture, and applying detailed balance, we obtained, with E in eV, σn,γ<930E-1/2 μb. The corresponding limit on the astrophysical reaction rate is <790 cm3 mol-1 s-1. Theoretical predictions of the reaction rate have exceeded our upper limit by factors of 3 50.
- Publication:
-
Physical Review C
- Pub Date:
- January 2003
- DOI:
- 10.1103/PhysRevC.67.015806
- Bibcode:
- 2003PhRvC..67a5806K
- Keywords:
-
- 25.60.-t;
- 97.10.Cv;
- 26.30.+k;
- 26.35.+c;
- Reactions induced by unstable nuclei;
- Stellar structure interiors evolution nucleosynthesis ages;
- Nucleosynthesis in novae supernovae and other explosive environments;
- Big Bang nucleosynthesis