p-208Pb reactions.

Abstract. It is pointed out that the production of certain isotopes with mass and charge close to the target ones can be attributed to specific channels and sometimes to specific reaction mechanisms in terms of binary collisions. The most striking case is the production of A+1 isotopes, which can be obtained through (p,) channels only. The contribution of pion-producing channels is also underlined for the production of Z+1 isotopes, although these channels are not exclusive in this case. The description of the production of all these isotopes can be considered as a good testing ground for intranuclear cascades concerning the treatment of the pionic degrees of freedom. Data for the proton-induced reactions on 208Pb and 209Bi are compared with the predictions of the recent version of the INCL4 model, which has especially been improved in the pion sector. Good agreement is generally obtained. It is however stressed that for A+1 isotopes, the agreement is obtained owing to the energy-dependence of the nucleon mean field and arguments are given to indicate why this energy-dependence shows up in these special reactions and not in most of the other observables. The production of the same isotopes in thick targets is also investigated. 1