The forward linear momentum transfer in reactions leading to fission between heavy ions such as ${\mathrm{C}}^{12}$, ${\mathrm{N}}^{14}$, ${\mathrm{O}}^{16}$, and ${\mathrm{Ne}}^{20}$ and the target nuclei Ho, Au, Bi, and ${\mathrm{U}}^{238}$ has been investigated by measuring the angular correlation between the fragments. The experimental values for the most probable parameters for center-of-mass transformation for these systems are compared with calculated values. For all the systems, the dominant reaction involves a full momentum transfer by the heavy ion to the fissioning nucleus. It is observed that for the system Au+${\mathrm{Ne}}^{20}$ and Bi+${\mathrm{Ne}}^{20}$, reactions with incomplete momentum deposition contribute 5.1% and 8.6%, respectively, to the total fission cross section. For ${\mathrm{U}}^{238}$ targets this admixture amounts to 12 to 17% for all ions at the highest bombarding energy and decreases with decreasing projectile energy. Possible reaction mechanisms leading to fission are suggested. A brief discussion of the method and its application is given.

• Received 7 September 1961

DOI:https://doi.org/10.1103/PhysRev.125.1350