MEASUREMENT OF THE LI-8(N,GAMMA) LI-9 CROSS-SECTION AT ASTROPHYSICAL ENERGIES BY REVERSE KINEMATICS

We have made the first attempt at determining the Li-8(n, gamma)Li-9 c ross section at astrophysical energies. This reaction competes with th e Li-8(alpha,n)B-11 reaction in-the inhomogeneous big bang model and w ith Li-8 beta decay in the r process. It may affect the primordial abu ndance and the stellar production of A>12 nuclei. Using a radioactive beam of Li-9 and the Coulomb dissociation method we attempted to measu re the cross section of the inverse reaction Li-9(gamma, n)Li-8. We re port only an upper limit because we were unable to determine and subtr act the nuclear dissociation. Through the detailed balance theorem, th is lead to an upper limit for the cross section of interest, Li-8(n, g amma) Li-9. The limit is 19 +/- 8 b for E-n = 0-500 keV or, when expre ssed as a reaction rate, 7200 cm(3) s(-1) mole(-1).