The Be-9(n,p)Li-9 reaction and the Gamow-Teller unit cross section

Double differential cross sections of the Be-9(n,p)Li-9 reaction have been measured at 96 MeV in the angular range 0 degrees-27 degrees up to about 20 MeV excitation energy. In addition, the C-12(n,p)B-12 reaction has been me asured in the same angular and excitation energy range. Cross sections fdr reactions leading to the ground state and the first excited state (2.69 MeV ) of Li-9 have been analysed using peak-fitting techniques. The data have b een compared with cross sections obtained from distorted-wave Born approxim ation calculations. A Gamow-Teller (GT) unit cross section for the ground s tate transition of 7.4 +/- 1.2 mb/sr was determined From the identified GT strength. Discrepancies in the Gamow-Teller unit cross sections for differe nt (n,p) and (p,n) transitions from the Be-9 ground state, resembling the s ituation for C-13, have been found. (C) 2000 Elsevier Science B.V. All righ ts reserved.