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 measured 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 been compared with cross sections obtained from distorted-wave Born approximation calculations. A Gamow-Teller (GT) unit cross section for the ground state transition of 7.4 +/- 1.2 mb/sr was determined From the identified GT strength. Discrepancies in the Gamow-Teller unit cross sections for different (n,p) and (p,n) transitions from the Be-9 ground state, resembling the situation for C-13, have been found. (C) 2000 Elsevier Science B.V. All rights reserved.