Résumé : We have measured cross sections of neutron-induced nuclear reactions leading to the delayed production of γ-ray lines similar to the ones of astrophysical interest. Conclusions were drawn concerning the expected background in the 26Al 1809 keV line and the 7Be 478 keV line in SPI. The neutron-induced degradation of Ge detectors was studied vs. the neutron energy, the neutron fluence and the detector temperature. Performance recovery of the detectors was studied for different annealing temperatures. Optimum temperature and times for annealing were determined.