Mechanisms of light-charged-particle emission in the matched reactions 905 and 1030 MeV ¹²¹Sb + ²⁷A1 and 550 and 750 MeV ⁸⁶Kr + ⁶³Cu

Emission of ⁴He and ¹H has been studied in the reactions 905 and 1030 MeV ¹²¹Sb + ²⁷Al and 550 and 750 MeV ⁸⁶Kr + ⁶³Cu, which lead to similar composite systems of ¹⁴⁹Tb^* (or ¹⁴⁸Gd^*). Energy spectra and angular distributions were measured for the light charged particles in coincidence with heavy fragments from fusion-fission (FF) and deeply inelastic reactions (DIR). These emissions are well described by three primary sources: the detected and partner (undetected) fragments (FE), and the composite system prior to scission (CE). The multiplicities derived for ¹H and ⁴He in coincidence with fission-like fragments or projectile-like fragments are much smaller than those associated with evaporation residues (ER). The multiplicity data indicate that the probability for CE emission decreases with increasing spin of the emitter. The characteristics of the CE particles detected in coincidence with DIR and FF are consistent with emission from a strongly distorted nuclear system en route toward scission. Strong evidence is presented confirming near-scission emission (NSE) as an additional source of charged particles. Comparisons of particle multiplicities for matched reactions revealed substantial differences in the FF and DIR processes which can be understood as resulting from different spin zones in the entrance channels.