Fission Measurement on 5.5 to 22 MeV/A²⁸Si +¹⁹⁷Au Systems (I) Linear Momentum Transfer and Angular Distribution off Reaction Plane

Abstract：

The velocities and angular distributions of correlated fission fragments emitted from reaction of ¹⁹⁷Au bombarded by a ²⁸Si beam with energies from 5.5 to 21.7 MeV/ Aare measured. The results show that when the incident energy is larger than 10 MeV/ A, the incomplete fusion-fission (ICF) associated with incomplete linear momentum transfer ( LMT) appears. Furthermore, when E _cm> 200 MeV, as a companion of ICF, the sequential fission (SF) with lower LMTthan that of ICF, has apparent yields. By comparing the difference of LMTvalues from ICF and SF, the ratio of SF over total fission cross-section has been obtained. Moreover, the angular distribution off the reaction plane of one fragment and its standard deviation have been obtained. It seems that there is a general linear relationship between the deviation and excitation energy per nucleon in heavier composite systems.